Adenomyomatous hamartoma of lung mimicking benign mucinous tumor in fine needle aspiration biopsy: a case report

BACKGROUND: Typical cytologic features of pulmonary hamartoma (PH) are usually smears of hyaline cartilage, fibrous tissue, smooth muscle, adipocytic components and respiratory epithelium. Cytologic features of adenomyomatous hamartoma, a special variant of PH, are not documented in the literature and are confused with epithelial neoplasm in the case of sparse stromal cellularity. CASE: A 59-year-old man presented with a solitary pulmonary nodule by chest radiograph at his routine health examination. Fine needle aspiration biopsy (FNAB) revealed numerous mucinous epithelial cells presenting predominantly in cohesive cellular sheets that suggested benign mucinous epithelial lesion. The patient underwent surgery for the tumor, and it was histologically proven to be an adenomyomatous hamartoma. CONCLUSION: An unusual type of PH could lead to misdiagnosis by FNAB in the case of few stromal components. This case demonstrates the wide spectrum of PH in FNAB and led us to consider PH as a differential diagnosis despite lack of chondromyxoid stromal components.     

Diagnostic Fine-Needle Aspiration Biopsy of an Intrathyroidal Parathyroid Gland and Subsequent Eucalcemia in a Patient with Primary Hyperparathyroidism

ObjectiveTo present the clinical course of a patient with persistent primary hyperparathyroidism (PHPT) whose intrathyroidal parathyroid gland was diagnosed by ultrasound-guided fine-needle aspiration biopsy (FNAB).MethodsWe describe the clinical course and laboratory, radiographic, and microscopic findings of a patient with persistent PHPT due to an intrathyroidal cystic parathyroid gland and review the relevant literature.ResultsA 74-year-old man with PHPT (presenting serum calcium concentration, 16.2 mg/dL; intact parathyroid hormone [PTH] concentration, 341 pg/mL) had surgical excision of the right superior, right inferior, and left inferior parathyroid glands, but the left superior parathyroid gland remained unidentified. Microscopic examination revealed parathyroid hyperplasia. Technetium Tc 99m sestamibi single-photon emission computed tomography imaging showed uptake in 2 foci, 1 on each side of midline in the neck. Reoperation with attention to the left neck failed to locate another parathyroid gland. Neck ultrasonography demonstrated a complex nodule within the right lower lobe of the thyroid. Results from FNAB of the solid component were consistent with parathyroid cells, and cystic fluid PTH concentration was greater than 1800 pg/mL. Nine months later, neck ultrasonography showed a hypoechoic area located posterior to the inferior pole of the right thyroid. The patient remained eucalcemic 16 months postprocedure.ConclusionAutoinfarction of the parathyroid gland and aspiration of cystic fluid may explain resolution of hypercalcemia. Although PHPT due to functioning parathyroid cysts is rare, and PHPT due to cystic parathyroid hyperplasia has been described, this is the first case report of a patient with persistent PHPT due to a functional parathyroid cyst whose diagnosis by FNAB was followed by eucalcemia. (Endocr Pract. 2008;14:80-86)     

Morphometry of pseudoepitheliomatous hyperplasia: objective comparison to normal and dysplastic oral mucosae

OBJECTIVE: To compare the architectural and morphometric features of pseudoepitheliomatous hyperplasia (PEH) associated with oral granular cell tumors (GCT), normal oral mucosa and oral epithelial dysplasia. STUDY DESIGN: Quantitative comparisons between the diagnostic entities were carried out at the tissue level by estimating the fractal complexity of the epithelial connective tissue interface and at the cellular level by analyzing the morphometric features of algorithmically segmented epithelial cell areas. RESULTS: Casewise multivariate analysis showed that the fractal properties produced a correct discrimination rate of 96.4% between PEH and normal mucosa. Cellular parameters gave a 100% correct discrimination rate between PEH and mild dysplasia. Combining the fractal and cellular properties also showed 100% discrimination between PEH and normal mucosa and between PEH and mild dysplasia. CONCLUSION: The results show that PEH associated with GCT displays quantifiable morphometric features that make it differentiable from normal oral mucosa and oral epithelial dysplasia.     

Sebaceous lymphadenoma identified by fine needle aspiration biopsy: a case report

BACKGROUND: Sebaceous lymphadenoma of the parotid gland is a rare benign neoplasm. This is the first reported case of fine needle aspiration biopsy (FNAB) findings for sebaceous lymphadenoma of the parotid gland. CASE: A 60-year-old male presented with painless, bilateral parotid swelling noted for 5 months. The swelling was more pronounced on the right. Examination revealed bilaterally prominent parotid glands with diffuse firmness but no discrete masses. There was no evidence of facial nerve dysfunction. Laboratory evaluation was negative for infectious and autoimmune etiologies. Magnetic resonance imaging revealed bilateral cystic parotid masses. FNAB of the right parotid was obtained to assist with preoperative counseling. It revealed lymphoid and salivary gland parenchymal cells. The patient underwent a right superficial parotidectomy. The surgical specimen of the parotid mass confirmed the diagnosis of sebaceous lymphadenoma on the tissue section. The contralateral parotid mass had not been excised at this writing. CONCLUSION: This report is the first to describe the FNAB findings of the unusual benign parotid neoplasm sebaceous lymphadenoma. Though the definitive diagnosis of any parotid mass requires tissue, generally obtained via parotidectomy, an FNAB diagnosis can be useful in counseling a patient prior to definitive biopsy.     

Fine needle aspiration biopsy in central giant cell lesion: a report of 3 cases

BACKGROUND: Fine needle aspiration biopsy (FNAB) is a safe and efficient diagnostic method used in numerous lesions of the head and neck region. However, its use in central giant cell lesion (CGCL) is rarely seen. CASES: Three cases of CGCL were initially diagnosed with FNAB, emphasizing the cytologic and immunocytochemical features. CONCLUSION: FNAB, particularly when associated with clinical, radiographic and laboratory examinations, plays an important role in the preliminary diagnosis of CGCL.     

Ectopic Intrathyroidal Nonfunctioning Parathyroid Cyst

ObjectiveTo describe a rare case of ectopic intrathyroidal parathyroid cyst (PC) in a 29-year-old woman who had been referred to us because of a multinodular goiter.MethodsWe review the clinical, laboratory, and radiographic findings as well as the treatment in our patient and provide a brief discussion of the associated literature.ResultsUltrasonography of the neck showed the presence of 2 thyroid nodules in the left lobe, the larger of which was solid and the smaller of which had a cystic appearance. A small nodular area was also found in the right thyroid lobe (diameter, less than 8 mm). A thyroid scan performed with technetium showed the absence of uptake by both left lobe nodules. Fine-needle aspiration biopsy (FNAB) of the 2 major nodular lesions revealed that the larger thyroid nodule was benign and the smaller was a cyst with clear fluid. Measurement of parathyroid hormone in the FNAB fluid showed a high concentration, suggestive of the diagnosis of PC. Normal serum levels of parathyroid hormone and calcium indicated that it was a nonfunctioning intrathyroidal PC. The PC disappeared after FNAB, but the lesion recurred 3 months later. Therefore, the patient underwent near-total thyroidectomy. Histologic examination confirmed the diagnosis of intrathyroidal PC, and a papillary microcarcinoma (6 mm in diameter) was found in the right lobe of the thyroid.ConclusionAlthough an ectopic intrathyroidal PC is rare, the frequency of occult papillary microcarcinoma of the thyroid is high. The association we describe, however, should be considered incidental. To our knowledge, this is the first report of an association of an intrathyroidal PC with papillary microcarcinoma of the thyroid. (Endocr Pract. 2007;13:56-58)     

Potential sampling error in fine needle aspiration biopsy of dedifferentiated chondrosarcoma: a report of 4 cases

BACKGROUND: Dedifferentiated chondrosarcoma is a rare, poorly understood and often fatal sarcoma that usually manifests as a high grade, non-cartilage-producing sarcoma juxtaposed against a low grade chondrosarcoma. A correct diagnosis requires recognition of both components. In the absence of complete resection, rendering a specific diagnosis on small biopsy specimens, such as fine needle aspiration biopsy (FNAB), may be extraordinarily difficult. CASES: We retrospectively reviewed 4 cytology samples (3 primary, 1 metastatic) from 3 patients with dedifferentiated chondrosarcoma, initially analyzed by FNAB, emphasizing the potential for sampling error. Two women, aged 78 and 57 years, both of whom had prior histories of carcinoma, presented with lesions involving the right and left femur, respectively. One 27-year-old man with multiple osteochondromatosis developed a dedifferentiated chondrosarcoma of the left pelvis. Two primary cytologic specimens consisted of moderately cellular smears containing a spindled to polygonal, nonspecific, pleomorphic sarcoma unaccompanied by definite matrix material; 1 of these had a concomitant core needle biopsy (CNB), also demonstrating pleomorphic sarcoma. The third primary cytologic specimen revealed low grade chondrosarcoma, but a concomitant CNB showed only a high grade, non-matrix-producing sarcoma. The last patient developed a metastasis to the opposite femur; FNAB revealed a high grade spindle cell sarcoma. In none of the FNAB or CNB specimens were both low and high grade components of dedifferentiated chondrosarcoma recognized. However, the diagnosis was strongly suspected based on the clinical and radiographic findings. CONCLUSION: Due to sampling error, the diagnosis of dedifferentiated chondrosarcoma may be difficult to establish by cytologic examination alone. Clinical and radiographic correlation is essential for an accurate diagnosis.     

Pulmonary epithelioid hemangioendothelioma: report of a case with fine needle aspiration biopsy

BACKGROUND: Pulmonary epithelioid hemangioendothelioma (PEH) is a rare, low grade, malignant vascular tumor that typically presents with multiple pulmonary nodules in young women. This report details the cytopathologic and pathologic findings in an unusual case presenting in an older male with a pleural effusion, dominant nodule and multiple bilateral infiltrates. CASE: A 62-year-old, male nonsmoker was referred due to increasing dyspnea. Chest radiography revealed a pleural effusion and nodular infiltrate in the right upper lobe of the bronchus. Thoracocentesis and thoracoscopy were performed, with a pleural drain inserted. Bronchoscopy revealed a right upper lobe bronchus occluded by a greyish, necrotic mass. Various cytopathologic sampling techniques, including fine needle aspiration biopsy, as well as traditional histopathologic biopsies were performed. Cytologic specimens showed loosely cohesive, epithelioid cells that were binucleated and multinucleated. Chromatin was granular, with scattered, small, multiple nucleoli with occasional, variably sized cytoplasmic vacuoles. The patient's condition deteriorated, and he died 3 weeks after admission. CONCLUSION: Pulmonary epithelioid hemangioendotheliomas are unusual neoplasms with a epithelioid, discohesive cellular appearance. It can mimic other, more commonly seen pulmonary neoplasms. Careful attention to cytomorphologic features and application of ancillary studies assist in making the diagnosis.     

Pseudomycetoma for microsporum canis: report of a case diagnosed by fine needle aspiration biopsy

BACKGROUND: Fine needle aspiration biopsy (FNAB) of the skin is useful in subcutaneous lesions. Dermatophytes are almost exclusively superficial cutaneous mycoses and constitute 70-80% of all mycoses and 5% of dermatologic consultations. Inflammatory and invasive forms, as well as infections that remain in chronic forms or persist in spite of treatment, are more frequent in immunocompromised individuals. The clinicalpresentations of these invasive cases are dermatopbytic granulomas (granuloma of Wilson-Majocchi and pseudomycetoma) or Hadida's disease. CASE: A 17-year-old male with an 8-year history of tinea capitis and multiple kerion lesions in the occipital region, left foot and right elbow resistant to conventional treatment was diagnosed by KOH tests and cultures as Microsporum canis. Two months before consultation he noticed the slow growth of a subcutaneous nodule in the base of the neck. FNAB of the neck nodule was performed. The diagnosis of pseudomycetoma by Microsporum canis was made. CONCLUSION: We report a case of pseudomycetoma caused by Microsporum canis, with the diagnosis made by FNAB. This case appears to be the first one diagnosed by this method in a human.     

Fine-needle aspiration biopsy cytology of cutaneous calcinosis in a 74-year-old woman with dermatomyositis on methotrexate therapy: a case report

BACKGROUND: Cutaneous calcinosis (CC) occurs in a variety of rheumatic diseases. Fine needle aspiration biopsy (FNAB) may be used in the office setting to evaluate such soft tissue lesions. For patients on methotrexate (MTX) therapy, methotrexate nodulosis (MN) should be considered in the differential diagnosis. CASE: A 74-year-old Caucasian woman with adult-onset dermatomyositis (ADM) on MTX therapy presented for evaluation of a right breast mass and multiple soft tissue nodules. FNABs of the right breast mass and a left upper extremity nodule both demonstrated benign calcified material. Six months later, the patient returned for evaluation of the persistent right breast mass and repeat FNAB revealed adenocarcinoma. Concurrently, a right hip soft tissue nodule was aspirated, demonstrating benign crystalline debris. MTX therapy was discontinued, and the patient subsequently underwent a lumpectomy of the right breast 1 month after FNAB diagnosis, displaying infiltrative ductal carcinoma. Of note, 2 months after her lumpectomy, MTX therapy was restarted and the patient continues to have adequate control of ADM symptoms with persistent, clinically benign soft tissue calcifications. CONCLUSION: Performing FNAB on soft tissue lesions can obviate needless tissue biopsies of CC in appropriate rheumatology patients, thus avoiding the risks and complications associated with more invasive procedures.     

Fine needle aspiration biopsy of precursor B-cell lymphoblastic lymphoma presenting as a sacral mass. A case report

BACKGROUND: Lymphoblastic lymphoma (LBL) is a high grade, aggressive neoplasm, usually presenting in children and young adults. Precursor B-cell LBL is uncommon and may present with cutaneous or, less likely, bone lesions. This case represents the first reported presentation of LBL as a sacral lesion and was only the second fine needle aspiration biopsy (FNAB) of LBL presenting as a bony mass. CASE: A 50-year-old man presented with a 3-month history of a 7 x 5 x 4-cm mass in the sacral region. The mass was radiologically described as an expansile one with lytic bone destruction. Diagnosis of a chordoma was radiologically favored. Computed tomography (CT)-guided FNAB, with flow cytometry and cytochemical staining, was used to make the diagnosis of precursor B-cell LBL. CONCLUSION: FNAB was instrumental in reaching this unusual diagnosis in a patient who was free of disease after chemotherapy.     

Crystals of alveolar soft part sarcoma in a fine needle aspiration biopsy cytology smear. A case report

BACKGROUND: Alveolar soft part sarcoma (ASPS) is a rare soft tissue tumor. It has characteristic histomorphology, with typical ultrastructural features demonstrating unique crystalloids. It occurs predominantly in adolescents and young adults, in whom the most common location is within the fascial planes of skeletal muscle of the lower extremity. CASE: We present fine needle aspiration biopsy (FNAB) findings along with histopathologic features and ultrastructural appearance of a large gluteal mass in a 29-year-old female. FNAB cytology smears showed single and small groups of polyhedral malignant cells with granular cytoplasm, anisokaryosis and prominent nucleoli. The delicate cytoplasm had a tendency to rupture, with the presence of many bare nuclei. The characteristic crystals were observed in Papanicolaou-stained smears within the cytoplasm and in the background near the tumor cells. This consolidated the radiologic suspicion of ASPS and facilitated the application of relevant ancillary tests. Biopsy of the mass showed the characteristic histologic pattern. Electron microscopy confirmed the diagnosis with demonstration of membrane-bound, rhomboid crystalloids with a latticelike ultrastructure. CONCLUSION: Detection of characteristic crystalloids in Papanicolaou-stained FNAB smears facilitated a proper evaluation and correct diagnosis of ASPS.     

Fine needle aspiration biopsy of neuroendocrine breast carcinoma metastatic to the thyroid. A case report

BACKGROUND: Tumors showing neuroendocrine differentiation arise in a wide range of organs, and metastatic neuroendocrine tumors may be difficult to differentiate from primary tumors. This report describes an unusual case of metastatic breast carcinoma with neuroendocrine differentiation that presented as a solitary thyroid nodule. The diagnosis was made by fine needle aspiration biopsy (FNAB). CASE: A 52-year-old woman presented with a thyroid nodule and bilateral enlarged supraclavicular fossa lymph nodes. FNAB revealed a neuroendocrine carcinoma. Further questioning revealed that the patient had had a breast carcinoma resected eight years previously. The diagnosis of metastatic neuroendocrine breast carcinoma was established by immunocytochemistry. The patient received antiestrogen therapy but subsequently developed skeletal metastases. CONCLUSION: Neuroendocrine carcinomas from various sites show similar cytologic features. In this case, a diagnosis of breast carcinoma metastatic to the thyroid was suggested by the clinical history and confirmed by FNAB with immunocytochemistry.     

Fine needle aspiration biopsy of primary mucinous carcinoma of the skin: a case report

BACKGROUND: Primary mucinous carcinoma of the skin is a rare neoplasm of sweat gland origin. To date there are only 2 case reports in English describing its features on fine needle aspiration biopsy (FNAB). We describe an additional case and review the literature regarding this entity. To the best of our knowledge, this is the first reported case with a sentinel lymph node biopsy. CASE: A 78-year-old woman presented with a 3-cm left scalp mass at an outside institution. Following incomplete excision, multiple subcentimeter nodules developed in the skin adjacent to the biopsy site. FNAB of the nodules confirmed a recurrence of mucinous carcinoma. Clinical examination and extensive radiographic studies did not reveal primary disease elsewhere, thus supporting a diagnosis of primary mucinous carcinoma of the skin. At the time of wide excision of the residual tumor, sentinel lymph node biopsy revealed a single focus of micrometastasis. The patient declined adjuvant therapy and was disease free 6 months after the initial diagnosis. CONCLUSION: Cutaneous mucinous carcinoma is a tumor characterized by bland histocytologic features and abundant extracellular pools of mucin. Without a high index of suspicion, this rare entity may be overlooked or misdiagnosed. Numerous benign and malignant mucin-producing primary and secondary mimics exist, and immunohistochemistry offers limited benefits in differentiating them. Cytologic diagnosis of primary mucinous carcinoma of the skin is possible; however, correlation of clinical, radiologic and pathologic features is necessary to arrive at an accurate diagnosis.     

Nodular sarcoid myositis of skeletal muscle diagnosed by fine needle aspiration biopsy. A case report

BACKGROUND: Symptomatic striated muscle involvement in sarcoidosis is rare. Muscle biopsy is usually required for the diagnosis. Fine needle aspiration biopsy (FNAB) has been successfully used in diagnosing soft tissue lesions. To the best of our knowledge, FNAB of sarcoid myositis has not been reported. CASE: A 31-year-old, black female with a history of sarcoidosis presented with an enlarging, painful, left calf mass. Infected thrombi were suspected. FNAB showed numerous loosely arranged epithelioid histiocytes, multinucleated giant cells and skeletal muscle cells. The overall cytologic picture was that of granulomatous myositis. The cytologic features coupled with the patient's history and magnetic resonance imaging findings suggested sarcoid myositis. Subsequent muscle biopsy showing noncaseating granulomata and negative stains for organisms confirmed the diagnosis of nodular sarcoid myositis. CONCLUSION: Nodular sarcoid myositis can be suggested by FNAB cytology in a patient with a past history of sarcoidosis.     

Fine needle aspiration biopsy of a posttransplant lymphoproliferative disorder with pronounced plasmacytic differentiation presenting in the face. A case report

BACKGROUND: Posttransplant lymphoproliferative disorders (PTLDs) occur in fewer than 2% of transplant patients. However, as a group, 54% of PTLD patients die of these diseases. Presentation as only skin/superficial soft tissue nodules is rare, with this the second such reported case, and this is the only fine needle aspiration biopsy (FNAB) of such a case as well as the only FNAB of a plasmacytoid monomorphous/monoclonal PTLD. CASE: A 48-year-old, white male, seven years status post kidney transplantation, presented with a 2.5-cm mass in the skin/soft tissue anterior to the right maxillary sinus. FNAB showed a moderately cellular smear composed of discohesive cells, many with the morphology of plasma cells and some with the morphology of large lymphocytes. Flow cytometry showed these cells to be a monoclonal B-cell population, and a diagnosis of monomorphous/monoclonal PTLD was made. The diagnosis was subsequently confirmed by histology. The patient ultimately died. CONCLUSION: The clinical course of the present patient was grave as compared with the course of the other reported patient.     

Fine needle aspiration cytology in lymphadenopathy of HIV-positive cases

OBJECTIVE: To evaluate the role of fine needle aspiration biopsy (FNAB) material in 25 HIV-positive cases with lymphadenopathy. STUDY DESIGN: We selected 25 cases for the present study who were enzyme-linked immunosorbent assay positive for HIV (HIV-1). FNAB was performed as a routine, outdoor procedure with informed consent of the patient. For each case, along with routine May-Grünwald-Giemsa and hematoxylin and eosin staining, Ziehl-Neelsen staining for acid-fast bacilli and periodic acid-Schiff staining for fungi were performed wherever necessary. RESULTS: A total of 28 sites were aspirated from 25 HIV patients. All these patients were heterosexual, and none had a history of drug abuse. FNAB was performed under ultrasound guidance in all four cases of a retroperitoneal group of lymph nodes. The most common FNAB diagnosis was reactive lymphoid hyperplasia (10), followed by tuberculosis (8). There were three cases diagnosed as fungal infection (two, Cryptococcus; one, histoplasmosis). FNAB of a case of lymph node was suggestive of tuberculosis. There was one case each diagnosed as non-Hodgkin's lymphoma and squamous cell carcinoma (metastatic). One case of a small axillary lymph node did not yield representative material. CONCLUSION: FNAB is a relatively inexpensive initial investigative technique in the diagnosis and management of HIV-positive patients. It can obviate the need for surgical excision and enable immediate treatment of specific infections.     

Cytologic diagnosis of alveolar soft part sarcoma of the lower extremity by fine needle aspiration and correlation with core biopsy: a case report

BACKGROUND: Alveolar soft part sarcoma is a rare soft tissue tumor of uncertain origin that is generally slow growing but unmistakably malignant due to its propensity for metastasis to lung, bone and brain early in the course of disease. Fine needle aspiration biopsy (FNAB) of these tumors and recognition of the characteristic cytologic features precludes more invasive diagnostic measures and facilitates appropriate treatment. CASE: A 54-year-old African-American man presented to our institution with a 2-week history of left leg pain. Imaging studies revealed a left leg soft tissue mass just below the popliteal fossa and multiple bilateral lung lesions suggestive of metastatic neoplasm. FNAB of the left lower extremity mass yielded uniform clusters of cells and sigle cells with large nuclei and single prominent nucleoli. Histologically, the biopsy showed nests of large polygonal cells with abundant eosinophilic cytoplasm, round regular nuclei and prominent nucleoli. A periodic acid-Schiff (PAS) stain highlighted intracytoplasmic rhomboidal crystals, a feature diagnostic of alveolar soft part sarcoma. CONCLUSION: Alveolar soft part sarcoma may be diagnosed by its unique morphologic characteristics and should be considered in the differential diagnosis of all cytologically sampled soft tissue lesions.     

Fine-Needle Aspiration Biopsy as a Preoperative Procedure in Patients with Malignancy in Solitary and Multiple Thyroid Nodules

Background

Fine-needle aspiration biopsy (FNAB) is a recognized technique for the basic, preoperative cytological diagnosis of thyroid nodules.

Aim of the Study

To analyze the accuracy of FNAB in the diagnosis of thyroid cancer in patients with solitary and multiple thyroid nodules and to compare the demographic, clinical and pathological characteristics of patients with thyroid carcinoma in solitary and multiple tumors.

Materials and Methods

The case records of 2,403 patients with solitary and multiple thyroid tumors treated consecutively between 2008 and 2013 were analyzed retrospectively. We selected 1,645 for further analysis. A solitary thyroid nodule was observed in 493 patients, and multiple nodules were detected in 1,152 patients. Further classification of the patients in these two groups was performed on the basis of the FNAB results, type of surgery performed and histopathology. TC was histopathologically confirmed in 166 patients, and benign disease was found in 1,479. The TC patients were assigned to the study group, and those with benign thyroid disease were placed into the control group. The study group was divided into two subgroups according to the presence of cancer in a single thyroid nodule or in multiple nodules. Malignancy in a solitary thyroid nodule was diagnosed in 98 (59.0%) patients, and cancer in multiple nodules was diagnosed in 68 (41.0%). Comparative analyses of the demographic, clinical and histopathological characteristics were performed for both subgroups. The following statistical analyses were performed: comparative characteristic of subgroups, ROC analysis for study group and subgroup of patients, and multivariable logistic regression analysis for study group.

Results

The rate of prediction of TC by FNAB was three times higher in the patients with a solitary thyroid nodule compared with those with multiple thyroid nodules and it was statistically significant (p<0.001). The rate of total thyroid resection and lack of necessity for reoperation were also significantly higher in the TC patients with a solitary nodule. The histopathological results showed that significantly more patients with a solitary nodule had advanced-stage TC (stage III or IV) and tumor progression (pT3 or pT4) (p = 0.002 for both). ROC analysis demonstrated that the overall accuracy of FNAB as a predictor of thyroid cancer presence was high, especially for the subgroup of patients with a solitary thyroid nodule (AUC = 0.958, p<0.0001). Multivariable logistic regression analysis confirmed that a positive FNAB result was the sole predictor of the performance of total resection in the TC study group (p<0.0001), while a negative FNAB result and the presence of a papillary cancer type were independent predictors of the risk of reoperation (p<0.0001 and p = 0.002, respectively).

Conclusions

FNAB often produces false-negative results in patients with multiple malignant thyroid tumors, which results in reoperation in many cases. False-negative FNAB results are rare in patients with a solitary tumor. Because of the low predictive capacity of FNAB for thyroid cancer in patients with multiple thyroid tumors, total thyroid excision should be considered in most cases despite a "negative" (no malignant) FNAB result.