Role of modified bleach method in staining of acid-fast bacilli in lymph node aspirates

OBJECTIVE: To correlate acid-fast bacilli (AFB) positivity with cytomorphologic patterns of tuberculous lymphadenitis and evaluate bleach concentration method in diagnosing lymph node tuberculosis compared to Ziehl-Neelsen (ZN) method. STUDY DESIGN: One hundred cases of tuberculous lymphadenitis diagnosed by fine needle aspiration cytology (FNAC) were analyzed and classified into 6 cytomorphologic patterns and correlated with bacillary load using routine and modified bleach methods of ZN staining. Smears were graded for AFB positivity. Sensitivity of routine ZN and modified bleach concentration was compared. RESULTS: The classic cytomorphologic pattern of tuberculosis showing epithelioid granulomas, Langerhans giant cells and caseous necrosis was seen in 23% of cases. Routine ZN staining detected AFB in 27% of cases and the modified bleach method in 72%. In 58 cases the modified bleach method had a higher grade of AFB positivity than the routine method. The modified bleach method did not miss any AFB positivity detected on routine ZN staining. CONCLUSION: The modified bleach method demonstrated AFB positivity in 72% of cases. AFB positivity grade was much higher than with routine ZN staining, making bacilli easily visible, with shorter screening time. The modified bleach method is inexpensive, easily performed and more sensitive and safe than routine ZN staining.     

Utility of papanicolaou stain-induced fluorescence in the cytodiagnosis of extrapulmonary tuberculosis

OBJECTIVE: To study the utility of Papanicolaou stain-induced fluorescence (PIF) in the detection of tubercle bacilli and to compare its diagnostic efficacy with that of the conventional Ziehl-Neelsen (ZN) method. STUDY DESIGN: This prospective study was carried out at a tertiary health care center, over a period of 2 years between January 2001 and December 2002. A total of 500 cases offine needle aspiration cytology from lymph nodes and other extrapulmonary sites were studied. Only cases that were clinically and cytologically suggestive of tuberculosis were included in the study. The smears were stained with ZN and Papanicolaou stain and examined under light and fluorescence microscopes, respectively for detection of acid-fast bacilli (AFB). Mycobacterial culture was used as the gold standard to compare the results. RESULTS: Cytologic smears were categorized into 4 distinct cytomorphologic patterns: epithelioid granulomas without caseous necrosis (101 cases), epithelioid granulomas with caseous necrosis (268 cases), caseation or acute inflammatory exudate only (114 cases), and occasional epithelioid cells without necrosis or giant cells (17 cases). The overall AFB positivity was 30.8% with the ZN method, while it was 40.6% with PIF. Moreover, PIF was more effective in detecting bacilli in group I lesions (18.8% vs. 6.9% with ZN method), in which the bacillary load is very low. CONCLUSION: PIF is superior to the conventional ZN method in detecting tubercle bacilli, particularly when the bacillary load is low. It is a relatively inexpensive and fast technique.     

Utility of repeat fine needle aspiration in acute suppurative lesions. Follow-up of 263 cases

OBJECTIVE: To determine the clinical value of repeat fine needle aspiration (FNA) as a follow-up strategy in the management of patients in India, clinically suspected of having tuberculosis (TB) but showing a cytologic picture of acute suppuration. STUDY DESIGN: Repeat aspirates from 263 patients presenting with lymph node or soft tissue masses were analyzed. The previous FNA of these cases had shown acute inflammatory exudate but no epithelioid granuloma or acid-fast bacilli (AFB). RESULTS: The repeat FNA helped to detect 55% additional cases of TB within a period of 8 weeks; 67% of them were diagnosed in the second and third weeks. Diagnostic yield rose to 59% after the third FNA. AFB were detected in 34 (13.3%) cases that showed a low bacterial load. In addition, nontubercular lesions, such as epidermal inclusion cyst (4), cysticercosis (3), sialadenitis (2) and metastatic carcinoma (8), were diagnosed. CONCLUSION: All cases showing acute suppuration without granulomas or AFB on the first FNA should be reevaluated by follow-up FNA and staining for AFB. This will enhance the diagnostic yield of tuberculosis in developing countries, where molecular diagnostics are too costly or unavailable. This procedure is cost effective as compared to biopsy and culture. In addition to tuberculosis, many unexpected nontubercular lesions may also be unmasked. Repeat FNA reduces sampling and screening errors, improves sensitivity and helps to study the evolution of epithelioid granulomas.     

Tubercular dactylitis: Fine needle aspiration cytology as a diagnostic modality

OBJECTIVE: To evaluate the efficacy of aspiration cytology in the early diagnosis of tuberculous dactylitis and describe the spectrum of cytomorphologic features in these cases. STUDY DESIGN: We studied 12 cases of dactylitis diagnosed as of tubercular etiology by fine needle aspiration cytology (FNAC) over a period of 6 years and assessed the clinicoradiologic features. The stained slides were reviewed and the spectrum of features noted. RESULTS: The most common clinical presentation was an indurated swelling of the involved digit (100%). On radiography, most often an expansile, lytic lesion along with soft tissue swelling was noted in 83% of cases. However, the clinical diagnosis did not consider a tubercular (TB) etiology. FNAC of these cases showed variable features; the most common was granulomas with or without necrosis (75% in total). Two cases showed acute suppurative cytology, and 1 revealed only fibroblasts and afew neutrophils. On the basis of suspicion, staining for acid-fast bacilli (AFB) was done in all cases, and bacilli were identified in all of them after a thorough search. These patients were soon started on antituberculous therapy, with significant improvements. CONCLUSION: FNAC can serve as an inexpensive and comparatively less invasive procedure for early diagnosis of TB dactylitis, permitting timely initiation of specific therapy. This study also highlighted the unusual cytomorphology in some cases. Clinicians and pathologists should maintain a high index of suspicion in cases of dactylitis and stain for AFB in all cases.     

Species-specific immunocytochemical localization of Mycobacterium tuberculosis complex in fine needle aspirates of tuberculous lymphadenitis using antibody to 38 kDa immunodominant protein antigen

OBJECTIVE: To examine immunocytochemical localization of Mycobacterium tuberculosis (MTB) complex antigen in fine needle aspiration (FNA) smears of tuberculous lymphadenitis (TBLN) using species-specific monoclonal antibody MTSS to 38-kDa immnunodominant protein antigen as a diagnostic adjunct to conventional cytomorphology and its advantage over Ziehl-Neelsen (ZN) microscopy. Study Design FNA smears from 340 cases-174 TBLN; 34 negative controls from nontuberculous, positive controls of 13 known acid-fast bacilli (AFB)-positive sputum smears; 50 blind controls; and 69 other controls (smears from stock cultures of bacterial, atypical mycobacteria and fungal species) were subjected to ZN and immunocytochemical staining using MTSS by the streptavidin-biotin method. RESULTS: Immunocytochemical staining was positive in 59 of 61 (96.7%) archival and 110 of 113 (97.3%) fresh FNA smears; ZN positivity for AFB was observed in 27 of 61 (44.2%) archival and 48 of 113 (42.4%) fresh FNA smears of TBLN. CONCLUSION: The immunostaining using MTSS showed a definite advantage over conventional ZN staining for detection and specific diagnosis of TBLN in FNA smears with 0% false positive results. Immunostaining of cytosmears with species specific antibody to MTB would prove to be a good diagnostic adjunct to morphologic diagnosis.     

Tuberculosis of the intercostal lymph nodes

OBJECTIVE: To describe tuberculosis of the intercostal lymph nodes and discuss its clinical and cytologic profile and pathogenesis. STUDY DESIGN: Fifteen cases from March 1994 to March 2000 were retrieved from our cytology records. Only clinically and therapeutically proven cases were included in the study. RESULTS: The ages of the patients ranged from 4 to 63 years. The male:female ratio was 2:1. The duration of disease at presentation ranged from one week to nine months. The lumps presented either in the parasternal region or between the midclavicular and posterior axillary lines. One case presented with an infrascapular lump. Most of the lumps were ill defined and cystic. Chest radiographs in all cases showed a soft tissue swelling without bony involvement. The aspirates were of two types, blood-mixed particles and necrotic material. Four cytologic pictures were seen: (1) epithelioid cell granulomas alone or (2) with necrosis or (3) with both necrosis and acid-fast bacilli (AFB), or (4) necrosis with AFB. AFB were detected in 53.3% of cases. CONCLUSION: If necrotic material is aspirated or if granulomatous inflammation is encountered in soft tissue swellings of the chest wall, particularly in the parasternal and axillary regions, the possibility of intercostal tuberculous lymphadenitis should be considered.     

Fine needle aspiration cytology in the diagnosis of tuberculous mastitis

OBJECTIVE: To study the relationship between granulomas in the breast and tuberculous mastitis. STUDY DESIGN: Retrospective analysis of 22 breast aspirates that showed epithelioid cell granulomas. The aspirates were reviewed and the cytomorphologic findings summarized. RESULTS: Aspiration cytology revealed epithelioid cell granulomas along with giant cells, necrosis and inflammatory cell infiltrate. Overall acid-fast bacillus (AFB) positivity was 22.7%. AFB positivity was greater in the presence of necrosis when epithelioid cells were absent. CONCLUSION: In a country like India, the diagnosis of granulomatous mastitis must be made with caution, even in the absence of AFB. Only after a sufficient trial of antituberculosis treatment has been given and the patient fails to respond should an alternative diagnosis be suggested.     

Esophageal tuberculosis. Endoscopic cytology as a diagnostic tool

OBJECTIVE: To study the utility of endoscopic cytology in the diagnosis of esophageal tuberculosis in clinically unsuspected cases. STUDY DESIGN: During a period of four years, endoscopic cytology of esophageal lesions was performed on 228 patients. In eight (3.5%) the cytologic diagnosis of esophageal tuberculosis was suggested on smears. Upon endoscopic examination, the sites of involvement were mid esophagus (five cases), upper esophagus (two cases) and lower esophagus (one case). Linear ulcer was seen in six cases; growth and narrowing of the lumen were seen in one case each. Endoscopic brush smears in seven cases and fine needle aspiration cytology smear in one case were collected. Air-dried smears stained by Giemsa stain were reviewed for detailed cytologic assessment. RESULTS: Smears showed well-defined granulomas with necrosis in five cases and granulomas without necrosis in three. Cytologic evidence of concurrent poorly differentiated squamous cell carcinoma was observed in one case. Tubercle bacilli were demonstrated in five cases. Endoscopic biopsy showed granulomas in three cases and tubercle bacilli in one case. In six cases there was no clinical or radiologic evidence of tuberculosis at other sites, thereby suggesting the possibility of primary esophageal tuberculosis. The remaining two cases had a past history of tuberculosis; one presented with cervical lymphadenopathy and one mediastinal lymphadenopathy. All patients received antitubercular treatment, and the patient with concurrent malignancy also received radiotherapy. All but one of the patients who succumbed to aspiration pneumonia responded to treatment. CONCLUSION: Endoscopic cytology is a useful modality in the diagnosis of esophageal tuberculosis in clinically unsuspected cases.     

Acid-fast bacilli in fine needle aspiration smears from tuberculous lymph nodes. Where to look for them

OBJECTIVE: To analyze where acid-fast bacilli (AFB) are most often seen in smears prepared from tuberculous lymph nodes. STUDY DESIGN: Patients referred for fine needle aspiration cytology for evaluation of lymphadenopathy between March 1994 and June 1998 were analyzed. Only those cases clinically and therapeutically proven to be tuberculous were included in the study. RESULTS: Of 783 cases analyzed, 213 (27.2%) were tuberculous. Aspirates obtained were of three types: blood-mixed particles, caseous material and pus. Five cytologic pictures were seen: epithelioid cell granulomas alone or with coexistent necrosis, AFB or both, and necrosis with AFB. AFB were most often seen in purulent aspirates, followed by caseous and least often in blood-mixed particles. Granulomas were most often seen when the aspirate was blood-mixed particles, followed by caseous and, least often, pus. CONCLUSION: AFB detection should be carried out on all suspected tuberculous patients. The relationship between the presence of granuloma and of AFB is inverse. The chance of finding AFB is highest in patients presenting with a cold abscess and yielding pus on aspiration followed by patients who yield caseous material on aspiration.     

Caseous, necrotic material and epithelioid cell granulomas in synovial fluid from a patient with tuberculous infection: a case report

BACKGROUND: The gross appearance and cytologic findings in synovial fluid in tuberculous infections are similar to those in other types of chronic synovial effusion. Demonstration of acid-fast bacilli (AFB) is required for a definitive diagnosis of tuberculous effusion; it is reported in only 20% of cases. The presence of frank caseous necrotic material and epithelioid cell granulomas in synovial fluid samples is unusual but strongly indicative of tuberculous infection. CASE: A 28-year-old man, on treatment for pulmonary tuberculosis, presented with a history of right ankle swelling, which was clinically interpreted as nonspecific synovitis. The synovial fluid was yellowish, with fluffy, whitish material. Cytologic smears showed abundant, caseous, necrotic material; a few histiocytic aggregates; and occasional epithelioid cell granulomas. Although stain for AFB was negative, considering the clinical presentation, a diagnosis of tuberculous synovitis could be rendered. CONCLUSION: Caseous, necrotic material and epithelioid granulomas in synovial fluid are highly unusual but, when present, can be considered definitive evidence of tuberculous effusion, particularly in a known case of pulmonary tuberculosis.     

Value of radiologically guided fine needle aspiration cytology (FNAC) in the diagnosis of spinal tuberculosis: a study of 29 cases

FNAC is a simple diagnostic tool for the initial evaluation of various deep seated pathological lesions. This study describes the applicability and practical aspects of the technique in establishing the diagnosis of spinal tuberculosis (TB) with the aid of radiographic guidance. The study was conducted in a major teaching hospital in Kuwait between the years 1985 and 1994. Twenty-nine patients (M:F = 18:11 and age range 8-72 years) with clinically and/or radiologically suspected spinal TB were seen in the Department of Cytology, Mubarak Al Kabeer Hospital. The patients were re-examined by either computed tomography (CT) scanning (n = 19) or fluoroscopy (n = 10) to localize the lesion for FNAC. FNAC smears were routinely stained with Papanicolaou and Diff Quik stains and one smear of each case was stained with Ziehl-Neelsen (Z-N) stain for acid-fast bacilli (AFB). Aspirated purulent material or syringe washings of dry aspirates were also submitted for microbiological cultures including AFB. Radiological and cytological findings were recorded in each case. Radiological findings included: bony rarefaction and destruction (93.1%), narrowed disc space (89.7%), soft tissue calcification (65.5%) and para-vertebral abscess formation (51.7%). Cytological findings included: epithelioid cell granulomas (89.7%), granular necrotic background (82.8%) and lymphocytic infiltration (75.9%). Smears were positive for AFB in 51.7% of cases. A positive AFB culture was obtained in 82.8% of cases, including all cases with positive AFB on smear by Z-N stain. Radiologically guided FNAC with AFB culture is a simple, reliable and practical approach to diagnosing spinal TB lesions. With a high diagnostic yield, it allows immediate initiation of specific treatment, helps to avoid invasive diagnostic procedures, and decreases hospitalization time.     

A comparative study on the different staining methods and number of specimens for the detection of acid fast bacilli

The presence of acid fast bacilli in multiple specimens was investigated comparatively with Ziehl-Neelsen (ZN) and fluorescence microscopy (FM) staining in order to determine sensitivity in detecting tuberculosis (TB). A total of 465 specimens obtained from 295 patients were analysed at Harran University Medical School Hospital between March 1998 and March 2000. The culture was employed as the reference method. Sixty-eight patients (23.1%) were diagnosed as having TB by culture. The ZN and FM staining sensitivities were 67.6% (46/68) and 85.2% (58/68) respectively. Two hundred and one patients (68.1%) submitted one specimen to the laboratory. TB positivity was detected in 42 (20.9%) of these patients by culture. The sensitivities of ZN and FM stains were found to be 61% and 83% in these patients. However, in 18 patients (6.1%) who submitted two specimens to the laboratory, the TB was positive in six of them (33.3%) and ZN and FM sensitivities were 66% and 83% respectively. When three specimens or more were collected from the patients (76 patients, 25.8%), TB positivity was determined in 20 of them (26.3%) and the sensitivities were 80% and 92% in the ZN- and FM-stained smears, respectively. Our data indicate that in the diagnosis of TB, FM has greater sensitivity than ZN. In particular, in the case of a single specimen, the diagnostic value of FM is quite significant. It is, therefore, possible to conclude that both ZN and FM staining can be used for the diagnosis of TB when there are more than two specimens. However, if only one or two specimens are available, FM staining is preferable.     

Thyroid tuberculosis – role of PCR in diagnosis of a rare entity

N. Gupta, K. Sharma, A. Barwad, M. Sharma, A. Rajwanshi, P. Dutta and A. Sharma
Thyroid tuberculosis – role of PCR in diagnosis of a rare entity Background: Tuberculosis is a rare cause of granulomatous thyroiditis, whose diagnosis may be difficult with routine cytopathology and staining for acid‐fast bacilli (AFB). Study design: Amongst 7962 cases of various thyroid lesions subjected to fine needle aspiration cytology (FNAC) over a period of 12 years, 34 cases (0.43%) were found to have cytological features of granulomatous inflammation with or without necrosis, which could be due to tuberculosis, granulomatous thyroiditis or other causes of granulomatous inflammation such as sarcoidosis or fungal infections. DNA was extracted from the material available on May‐Grünwald–Giemsa‐stained smears from the archival material. PCR for Mycobacterium tuberculosis was performed for insertion sequence IS6110. Results: The age of the patients ranged from 32 to 58 years (median 48 years); 24 were female and 10 male. FNAC from thyroid swellings showed epithelioid granulomas with giant cells and/or necrosis. Although acid‐fast bacilli were only seen in smears in two cases, 19/34 (55.9%) showed the presence of 123 bp DNA band under ultraviolet transillumination. Five control cases were negative. Conclusion: Our study of archival cytological material illustrates the importance of PCR as a potentially useful tool for the detection of M. tuberculosis DNA from FNAC of thyroid lesions, which could provide an alternative for rapid diagnosis of thyroid tuberculosis in AFB‐negative cases.     

Fine needle aspiration biopsy in the diagnosis of tuberculosis

Bacteriologic data and aspiration smears obtained by fine needle aspiration (FNA) biopsy for a series of 39 cases of tuberculosis were reviewed. Based on the morphologic features of the aspiration smears, the cases were divided into two groups: 18 cases in which distinct epithelioid granulomas were present and 21 in which no granulomas were found but large amounts of necrotic debris with variable numbers of polymorphonuclear cells, histiocytes and lymphocytes were present. Material from the FNA biopsy specimen was submitted for culture and fluorescence studies in 34 cases (15 with and 19 without granulomas). In the first group, auramine-rhodamine staining of smears was positive in 4 of 15 cases and Mycobacterium tuberculosis was isolated in 12 of 15 cases. In the second group, auramine-rhodamine staining was positive in 9 of 19 cases and culture was positive for M. tuberculosis in 16 of 19 cases. The results indicate that studying FNA smears by light microscopy and bacteriologic culture is an effective way of diagnosing tuberculosis.     

Fine needle aspiration cytology in HIV‐related lymphadenopathy: experience at a single centre in north India

P. K. Sarma, A. K. Chowhan, V. Agrawal and V. Agarwal
Fine needle aspiration cytology in HIV‐related lymphadenopathy: experience at a single centre in north India Objective: Fine needle aspiration (FNA) is emerging as a rapid and minimally invasive tool in evaluating lymphadenopathy associated with human immunodeficiency virus (HIV). We evaluated the role of FNA in differentiating various causes of lymphadenopathy in patients with HIV and correlated the cytological diagnosis with CD4 counts. Methods: Seventy‐nine HIV‐positive patients (median age 35 years, 68 male) underwent ultrasound‐guided (n = 16) and unguided (n = 63) FNA from 1999 to 2006. Smears were stained with May–Grünwald–Giemsa, haematoxylin & eosin and Papanicolaou stains. Ziehl–Neelsen (ZN) staining for acid‐fast bacilli (AFB) was performed in all cases. Staining for fungus was performed whenever required. Results: The aspirates were adequate in 75 cases (95%). Non‐specific reactive hyperplasia was the most common FNA diagnosis (39, 52%) followed by granulomatous necrotizing lymphadenitis (15, 20%), necrotizing lymphadenitis (13, 17.3%) and granulomatous lymphadenitis (4, 5.2%). Fungal infection and non‐Hodgkin lymphoma (NHL) were seen in two patients each. ZN staining was positive for AFB in 25 (33.3%) cases. One of these was morphologically interpreted as reactive hyperplasia, 12 as necrotizing lymphadenitis and 12 as granulomatous necrotizing lymphadenitis. Both patients with NHL had CD4 counts below 100/dl. Necrotizing lymphadenitis and granulomatous lymphadenitis were significantly associated with CD4 counts below and above 200/dl, respectively (P = 0.0002). Conclusions: FNA is an important tool for assessing the cause of lymphadenopathy in HIV patients. Necrotizing inflammation is more often seen in patients with low CD4 counts. AFB are commonly found in necrotic aspirates with or without granulomas. However, a stain for AFB should be performed in all aspirates from HIV‐related lymphadenopathy including reactive hyperplasia.     

Diagnosing granulomatous inflammation of the skin. A cytomorphologic approach based on evaluation of cellular reaction patterns.

OBJECTIVE: To determine the applicability of recognizing cellular reaction patterns in the cytologic diagnosis of granulomatous inflammation of the skin. STUDY DESIGN: Prospective. Two hundred seventeen cases of clinically suspected granulomatous dermatitis formed the data for this study. May-Grünwald-Giemsa, Ziehl-Neelsen, periodic acid-Schiff, silver impregnation and Gram staining methods were employed. RESULTS: Five cytomorphologic patterns of granulomatous inflammation were identified: epithelioid cell granulomas (77), histiocytic granulomas (20), epithelioid cell granulomas with polymorphous exudate (77), foreign body granulomas (3) and fat necrosis with granulomas (9). CONCLUSION: Correlating clinical presentation with cytomorphologic patterns often yields diagnostic information in the workup of granulomatous inflammation of the skin and frequently obviates the need for biopsy.     

Fine needle aspiration cytology of tubercular epididymitis and epididymo-orchitis

OBJECTIVE: To study the role of fine needle aspiration cytology (FNAC) and ancillary studies in the diagnosis of tubercular epididymitis or epididymo-orchitis. STUDY DESIGN: Forty patients with tubercular epididymitis or epididymoorchitis diagnosed on FNAC underwent a detailed clinical workup, imaging and microbiologic studies before being started on antitubercular treatment (ATT). One patient underwent orchiectomy. RESULTS: Clinically, the disease presented in patients of all ages usually as a scrotal swelling or rarely as a scrotal sinus (3) or abscess (3) or as part of disseminated tuberculosis (2). Three patients gave a history of previous tuberculosis. Scrotal sonography confirmed the involvement of the epididymis, testis or spermatic cord in each case. FNAC was diagnostic in 27 aspirates (epithelioid cell granulomas with caseation) but nondiagnostic in the rest. Tubercular etiology was confirmed directly by detection of acid-fast bacilli (AFB) on FNA smears in 24 (60%) patients and urine samples in 11 and indirectly in 9 patients with negative AFB by using a combination of a positive Mantoux test (5 of 9), presence of caseating granulomas on FNA smears (7 of 9) and therapeutic response to ATT (9 of 9). CONCLUSION: FNA as a minimally invasive technique plays a prime role in the diagnosis of tubercular epididymitis and epididymoorchitis. It provides adequate material for cytologic and microbiologic examination and helps to avoid unnecesary orchiectomy.     

Location of intra- and extracellular M. tuberculosis populations in lungs of mice and guinea pigs during disease progression and after drug treatment

The lengthy treatment regimen for tuberculosis is necessary to eradicate a small sub-population of M. tuberculosis that persists in certain host locations under drug pressure. Limited information is available on persisting bacilli and their location within the lung during disease progression and after drug treatment. Here we provide a comprehensive histopathological and microscopic evaluation to elucidate the location of bacterial populations in animal models for TB drug development.To detect bacilli in tissues, a new combination staining method was optimized using auramine O and rhodamine B for staining acid-fast bacilli, hematoxylin QS for staining tissue and DAPI for staining nuclei. Bacillary location was studied in three animal models used in-house for TB drug evaluations: C57BL/6 mice, immunocompromised GKO mice and guinea pigs. In both mouse models, the bacilli were found primarily intracellularly in inflammatory lesions at most stages of disease, except for late stage GKO mice, which showed significant necrosis and extracellular bacilli after 25 days of infection. This is also the time when hypoxia was initially visualized in GKO mice by 2-piminidazole. In guinea pigs, the majority of bacteria in lungs are extracellular organisms in necrotic lesions and only few, if any, were ever visualized in inflammatory lesions. Following drug treatment in mice a homogenous bacillary reduction across lung granulomas was observed, whereas in guinea pigs the remaining extracellular bacilli persisted in lesions with residual necrosis. In summary, differences in pathogenesis between animal models infected with M. tuberculosis result in various granulomatous lesion types, which affect the location, environment and state of bacilli. The majority of M. tuberculosis bacilli in an advanced disease state were found to be extracellular in necrotic lesions with an acellular rim of residual necrosis. Drug development should be designed to target this bacillary population and should evaluate drug regimens in the appropriate animal models.     

Cytologic changes in small hepatocellular carcinomas after radiofrequency ablation

OBJECTIVE: To illustrate the cytologic changes in hepatocellular carcinoma (HCC) after radiofrequency ablation (RFA). STUDY DESIGN: The study included 20 patients with 23 HCC who had undergone RFA under ultrasound guidance. Baseline cytomorphology of HCC was evaluated by fine needle aspiration (FNA) in all cases. Triphasic helical computed tomography (CT) and FNA cytology were done to evaluate the efficacy of the treatment within two weeks after RFA. The cytologic specimens were stained with Riu's method (Romanowsky stain). RESULTS: A range of cytologic findings after RFA was found, including granular and amorphous debris with artefactual aggregation, degenerated cells or necrotic material, and dyshesive, degenerated cells in a necrotic background. The cytologic patterns included necrotic cells and debris in 14 tumors and fine, granular necrosis in 9. Helical CT showed no enhancement in any of the tumors after RFA. CONCLUSION: The cell patterns indicated complete necrosis in HCC after RFA.     

Diagnosis of extrapulmonary tuberculosis by PCR

During the last two decades, the resurgence of tuberculosis (TB) has been documented in both developed and developing nations, and much of this increase in TB burden coincided with human immunodeficiency virus (HIV) epidemics. Since then, the disease pattern has changed with a higher incidence of extrapulmonary tuberculosis (EPTB) as well as disseminated TB. EPTB cases include TB lymphadenitis, pleural TB, TB meningitis, osteoarticular TB, genitourinary TB, abdominal TB, cutaneous TB, ocular TB, TB pericarditis and breast TB, although any organ can be involved. Diagnosis of EPTB can be baffling, compelling a high index of suspicion owing to paucibacillary load in the biological specimens. A negative smear for acid-fast bacilli, lack of granulomas on histopathology and failure to culture Mycobacterium tuberculosis do not exclude the diagnosis of EPTB. Novel diagnostic modalities such as nucleic acid amplification (NAA) can be useful in varied forms of EPTB. This review is primarily focused on the diagnosis of several clinical forms of EPTB by polymerase chain reaction (PCR) using different gene targets.