Cystic fluid and fine needle aspiration cytopathology of cystic adult granulosa cell tumor of the ovary: a case report

BACKGROUND: Fine needle aspiration (FNA) is a valuable tool in the diagnosis of ovarian cysts, especially in the young and when a nonneoplastic cyst is suspected. A case is presented with its cystic fluid, FNA and imprint cytopathology findings diagnosed as cystic adult granulosa cell tumor of the ovary (AGCT). CASE: Cystic fluid and FNA material of a 24-year-old female patient with a left-sided cystic ovarian mass 11.5 cm in diameter was sent intraoperatively for cytopathologic examination. In aspiration cytopathology of AGCT, the presence of regular tumor cells with or without nuclear grooves arranged in a follicular pattern mimicking a Call-Exner body has been regarded as the characteristic cellular feature of the tumor. CONCLUSION: For correct interpretation of the cytopathologic findings, close communication with the clinician performing the aspiration is of vital importance.     

卵巢囊性颗粒细胞瘤的临床病理学特征、诊断及鉴别诊断

目的:探讨卵巢囊性颗粒细胞瘤的临床病理学特征、诊断和鉴别诊断要点。方法:复习1例卵巢囊性颗粒细胞瘤患者的临床资料、肿物的大体以及镜下病理组织学特征、免疫组化染色特征。结果:患者左侧单房囊性颗粒细胞瘤,大小为14.6 cm×18.9 cm×9.8 cm,囊壁厚薄不均一;镜下可见内壁由颗粒细胞组成,细胞层数不一,可见典型的Call-Exner小体;免疫组化染色可见α-inhibin,Vimentin,CD99均阳性。结论:卵巢囊性颗粒细胞瘤可依据镜下发现不典型增生的颗粒细胞、典型的Call-Exner小体和核沟等特征性的组织形态学作出诊断。     

Fine needle aspiration cytology of an ovarian luteinized follicular cyst mimicking a granulosa cell tumor. A case report

BACKGROUND: Fine needle aspiration is a valuable tool in the diagnosis of ovarian cysts, especially in the young and when a nonneoplastic cyst is suspected. High cellularity, epitheliallike clusters and cellular atypia in aspirates from functional cysts are known features that may lead to an erroneous diagnosis of malignancy. Granulosa cells in ovarian cystic fluids may originate in follicular cysts or cystic granulosa cell tumors. In luteinized follicular cysts the cells usually have ample cytoplasm and tend to form clusters. This report draws attention to a case where abundant, dispersed cells lacking cytoplasm led to the incorrect diagnosis of a granulosa cell tumor. CASE: In an ovarian cystic aspirate from a 34-year-old woman, the fluid was highly cellular, with a striking predominance of cells interpreted as granulosa cells. Granulosa cells are often found in aspirates from functional cysts, but striking cellularity, prominent nuclear grooves and lack of luteinization made us consider a granulosa cell tumor rather than a follicle-derived cyst. Surgery was performed, and histology revealed a benign serous cystadenoma but also numerous maturing follicles and follicular cysts with thick layers of granulosa cells. The aspirate obviously did not represent the cystadenoma but one of the prominent follicular cysts. CONCLUSION: An understanding of the cytologic features of functional ovarian cysts, including the pitfalls, is necessary to avoid a false diagnoses of a neoplastic lesion. For a correct interpretation of the cytologic findings, close communication with the clinician and with the radiologist performing the aspiration is of vital importance.     

Cytologic features of ovarian granulosa cell tumor metastatic to the lung. A case report

BACKGROUND: Granulosa cell tumor (GCT) of the ovary is an uncommon but not rare tumor, and the adult type usually affects postmenopausal women. The adult type of GCT has several characteristic clinicopathologic features, including a composition of small, uniform cells with Call-Exner bodies and an ability to metastasize to extrapelvic organs, even several decades after the initial operation. CASE: A 62-year-old female was incidentally found to have multiple shadows in the peripheral portions of both lung fields on roentgenography. She had a past history of oophorectomy for an ovarian carcinoma more than 20 years earlier. A transbronchial lung biopsy series was nondiagnostic. An aspirate obtained by transthoracic fine needle aspiration (FNA) biopsy revealed clusters of rather uniform, small cells with nuclear grooves, suggestive of a metastatic lung tumor. Histologic examination of the lung tissue in comparison with the previous oophorectomy specimen confirmed the impression of GCT metastatic to the lung. CONCLUSION: A preoperative diagnosis of metastatic lung tumor was established by transthoracic FNA cytology. The important cytologic criteria for the differential diagnosis are uniformity of tumor cells, coffee bean-like nuclear grooves and Call-Exner bodies. The possibility of late recurrence of this kind of tumor, even two or three decades after surgical resection, should be kept in mind.     

Ultrastructure and composition of Call-Exner bodies in bovine follicles

Call-Exner bodies are present in ovarian follicles of a range of species including human and rabbit, and in a range of human ovarian tumors. We have also found structures resembling Call-Exner bodies in bovine preantral and small antral follicles. Hematoxylin and eosin staining of single sections of bovine ovaries has shown that 30% of preantral follicles with more than one layer of granulosa cells and 45% of small (less than 650 microns) antral follicles have at least one Call-Exner body composed of a spherical eosinophilic region surrounded by a rosette of granulosa cells. Alcian blue stains the spherical eosinophilic region of the Call-Exner bodies. Electron microscopy has demonstrated that some Call-Exner bodies contain large aggregates of convoluted basal lamina, whereas others also contain regions of unassembled basal-lamina-like material. Individual chains of the basal lamina components type IV collagen (alpha 1 to alpha 5) and laminin (alpha 1, beta 2 and delta 1) have been immunolocalized to Call-Exner bodies in sections of fresh-frozen ovaries. Bovine Call-Exner bodies are presumably analogous to Call-Exner bodies in other species but are predominantly found in preantral and small antral follicles, rather than large antral follicles. With follicular development, the basal laminae of Call-Exner bodies change in their apparent ratio of type IV collagen to laminin, similar to changes observed in the follicular basal lamina, suggesting that these structures have a common cellular origin.     

Progesterone, 17α-hydroxyprogesterone,androgens and oestrogens in bovine ovarian cysts

The concentration of steroid hormones in cystic follicular fluid was determined in cows with cystic ovaries. There was a significant difference in concentrations of the hormones from the cysts with granulosa cell layers, and the cysts without granulosa cell layers or only 2 to 3 layers with pycnotic nuclei in the granulosa cells (P < 0.01). The cystic follicles that consist of both thecal- and granulosa cell layers contained a low amount of progesterone and high levels of 17α-hydroxyprogesterone, androgens and oestrogens, not different from preovulatory follicles.In contrast, cysts that consist only of thecal cell layers contained a very high amount of progesterone, but very low levels of 17α-hydroxyprogesterone, androgens and oestrogens. That is functionally similar to the bovine corpus luteum which produces high concentrations of progesterone but has no or very low 17α-hydroxylase activity.In conclusion, the cystic follicles without granulosa cells are not capable of secreting 17α-hydroxyprogesterone, androgens and oestrogens, in spite of high levels of progesterone. It may be suggested that in these cysts there is a blockade of 17α-hydroxylase activity.     

Fine needle aspiration cytology of follicular variant of papillary carcinoma of the thyroid: Morphologic pointers to its diagnosis

OBJECTIVE: To study the cytomorphologic features of 59 cases of histologically proven follicular variant of papillary carcinoma (FVPC), compare them to those described in the literature and highlight cytologic features that may aid in the preoperative diagnosis. STUDY DESIGN: Aspiration smears from 59 histologically proven cases of FVPC were examined independently by 2 observers, and a detailed cytologic evaluation was done for architectural, cytologic and nuclear features. surgical RESULTS: On initial cytology of the 59 cases, 36 (61%) were diagnosed aspapillary carcinoma, and 17 of these were subtyped as FVPC. On reviewing the smears, 50 cases were diagnosed as papillary carcinoma, and 33 of them were typed as FVPC; however, 4 cases were diagnosed as benign lesions. Most smears showed moderate to high cellularity, with 55 cases (93%) showing syncytial clusters and 48 (81%) showing microfollicular architecture. Chromatin clearing and nuclear grooves were seen in 55 (93.2%) and 54 (91.52%) cases but were easily detected in only 36 (61%) and 44 (74%) cases, respectively. Thick colloid was identified in 28 cases, and 3 of these cases also showed thin colloid in the background. CONCLUSION: Our findings suggest that syncytial clusters, microfollicular architecture, chromatin clearing and nuclear grooves are strong morphologic pointers to the diagnosis of FVPC.     

Aspiration cytology of 147 adnexal cysts with histologic correlation.

OBJECTIVE: To assess the usefulness of cytology in the diagnosis of 147 histologically established adnexal cysts. STUDY DESIGN: Retrospective, macro-microscopic study based on fluid aspirated from 132 ovarian and 15 extraovarian cysts and projected as a cytohistologic correlation. RESULTS: Typical macroscopic features were identified in 76% of endometriotic cysts, in 53% of mucinous neoplasms and in 67% of dermoid cysts. Cytology helped to identify 67% of nonneoplastic and 56% of neoplastic cysts. The lowest diagnostic sensitivities were observed in functional cysts and benign serous neoplasms (50%), while the highest were shown by endometriotic cysts (76%) and malignant epithelial neoplasms (71%). Inadequate samples were obtained from all types of cysts, even malignant ones (two mucinous cystadenocarcinomas). Diagnostic cytology was useless in extraovarian cysts (33% sensitivity). An adult granulosa cell tumor was erroneously diagnosed as a follicular cyst by cytologic examination. CONCLUSION: Examination of the cyst fluids obtained by aspiration demonstrated low sensitivity, with 43% of inadequate samples obtained from all types of cysts. Malignant cystic neoplasms may be overlooked in inadequate samples. Our study also revealed that specificity in this type of analysis is high in inadequate samples, provided that the technique is carried out correctly.     

Cytologic features of granulosa cell tumors in fluids and fine needle aspiration specimens

OBJECTIVE: To describe the cytologic features of granulosa cell tumors in fluids and fine needle aspiration specimens, with histologic confirmation. STUDY DESIGN: Histologically confirmed granulosa cell tumors, 6 adult type and 1 juvenile type, were identified. All patients had local recurrences or metastases. Eleven specimens from 7 patients, including cytologic samples, cell blocks and histology, were reviewed. Inhibin immunostaining was performed on cell blocks to aid identification of this group of tumors in the cytologic and histologic samples. RESULTS: The patients were 22-72 years old. Sites included ovary and peritoneum; there were pelvic recurrences and metastatic lesions in the spleen, liver, perirectum and cervical lymph node. Cytologic features of adult granulosa cell tumors included 3-dimensional clusters, resettes loose monolayers and individual cells. Other features were Call-Exner bodies, vacuolated cytoplasm, exuberant capillaries associated with papillarylike fronds, a second population of elongated theca cells, and prominent or rare nuclear grooves. In juvenile granulosa cell tumor the features observed were monolayers, loosely cohesive sheets, single cells, occasional larger pleomorphic cells with nuclear clefting and nuclear protrusions, vacuolated cytoplasm, finely granular chromatin and frequent mitoses. The overall cytologic and histologic correlation was good. Inhibin was focally positive in one peritoneal fluid, correlating with the focal pattern of staining seen on histology. CONCLUSION: A definitive cytologic diagnosis of granulosa cell tumor can be made based on the above criteria. Aggressive tumors are discohesive and show pleomorphism and nuclear protrusions. Inhibin stain may be helpful in identifying granulosa cell tumors in cell block specimens.     

Immunocytochemical staining of ovarian cyst aspirates with monoclonal antibody against inhibin

mccluggage w. g., patterson a., white j. and anderson n. h. (1998) Cytopathology 9, 336–342
Immunocytochemical staining of ovarian cyst aspirates with monoclonal antibody against inhibin
Inhibin is a peptide hormone which is produced by ovarian granulosa cells during normal follicular development. It is important that granulosa cells are recognized in fine needle aspirates (FNAs) of ovarian cystic lesions, as this allows definite recognition of a functional cyst and exclusion of a potentially neoplastic epithelial lined cyst. Occasionally the distinction between granulosa and epithelial cells may be difficult, especially when aspirates from functional cysts are unusually cellular. In the present study, FNAs from 33 ovarian cystic lesions were immunostained with a monoclonal antibody against inhibin. Nine cases of peritoneal fluid containing malignant cells in patients subsequently confirmed to have ovarian adenocarcinoma were also stained. Where possible the cytological and immunocytochemical findings were correlated with subsequent biopsy. In most cases in which cytology suggested a functional cyst there was a strong positive staining with anti-inhibin, although occasional cases were negative. One case originally thought to contain epithelial cells stained strongly positive with anti-inhibin and on review was felt to represent a cellular functional cyst. In all other cases where cells were considered to be epithelial there was no staining with anti-inhibin. The study shows that immunocytochemical staining with anti-inhibin may be of value in confirming the presence of granulosa cells, thus establishing a diagnosis of functional cyst. Although negative staining does not exclude a functional cyst, positive staining with anti-inhibin allows exclusion of an epithelial lined cyst and may avoid unnecessary surgical intervention.     

Fine needle aspiration cytology in ovarian lesions: an institutional experience of 584 cases

N. Gupta, A. Rajwanshi, L. K. Dhaliwal, N. Khandelwal, P. Dey, R. Srinivasan and R. Nijhawan
Fine needle aspiration cytology in ovarian lesions: an institutional experience of 584 cases Objective: To assess the diagnostic value of fine needle aspiration cytology (FNAC) in ovarian lesions. Methods: This was a retrospective study of ultrasound‐guided (US) FNAC of 584 ovarian lesions from January 1998 to July 2010. The lesions were categorized into non‐neoplastic lesions, neoplastic lesions and inadequate aspirates. The results were compared with the corresponding histopathology whenever available. Results: Of the 584 lesions, 180 (30.8%) were reported as non‐neoplastic (48 non‐specific inflammation, 11 tuberculosis, 63 functional cysts and 58 endometriotic cysts), 249 (42.6%) as neoplastic (81 benign lesions/tumours and 168 malignant) and 155 (26.5%) as inadequate. Based on the subsequent histopathology, which was available in 121 (20.7%), the cases were divided into those that were concordant and discordant. Concordant cases comprised 92/121 (76%), including 28 non‐neoplastic lesions (seven non‐specific inflammation, nine functional cysts and 12 endometriotic cysts), 42 surface epithelial tumours (13 benign and 29 malignant), 10 germ cell tumours (five mature cystic teratomas and five mixed germ cell tumours), seven sex‐cord stromal tumours (three granulosa cell tumours, one sclerosing stromal tumour, one strümal leutoma, one Sertoli Leydig cell tumour and one malignant Sertoli cell tumour) and five miscellaneous lesions (one plasma cell tumour, two leiomyosarcomas and two cases of necrosis). Discordant cases comprised 29/121 (24%) (21were inconclusive or inadequate on cytology), including four endometriotic cysts, 14 surface epithelial tumours (one cystadenofibroma, one borderline mucinous tumour and 12 carcinomas), five germ cell tumours (two immature teratomas and three mature cystic teratomas), two thecomas, one fibroma, one sclerosing stromal tumour, one fibrosarcoma and one myxoma. FNAC sensitivity for a diagnosis of malignancy was 85.7%, specificity 98.0%, positive predictive value 97.7%, negative predictive value 87.7% and accuracy 92.0%, if 21 inconclusive/inadequate FNACs were excluded; with the latter taken as false negatives, sensitivity was 73.7% and accuracy 76.0%. Conclusion: FNAC has a high specificity for diagnosis of ovarian/adnexal lesions but greater experience is required for the accurate subtyping of neoplasms and sensitivity is limited by inconclusive/inadequate results.     

Ultrastructural and histochemical investigations of Call-Exner bodies in rabbit Graafian follicles

In a histological survey of 19 mammalian species, Call-Exner bodies of conventional size and appearance were found in only 5, namely, human, rhesus monkey, rabbit, guinea-pig and sheep. Rabbit ovaries were used for characterizing these bodies using quantitative histochemistry, lectin binding and electron microscopy. Call-Exner bodies were topographically distinct lacunae of the extracellular space probably containing hyaluronic acid with proteoglycan complexes. The staining characteristics of the antrum and Call-Exner bodies were generally similar. However, in contrast to the antrum, the smaller lacunae contained suspended filaments with a distinctive peripheral membrane upon which a rosette of granulosa cells was resting. The membrane and narrow intercellular clefts probably prevent much exchange of large glycosaminoglycan complexes with the antrum. The origin and significance of Call-Exner bodies require further study, but it is clear that they are associated with secretion rather than with necrosis as sometimes suggested.     

Giant cystic metaplastic carcinoma of the breast: a case report with diagnosis by fine needle aspiration

BACKGROUND: Breast cysts are mainly benign and are reported in association with fibrocystic disease and phyllodes tumor. Rarely have cystic changes been reported to occur in malignant tumors. They are usually small but large in rare cases. Giant breast cysts are very rare, and only a few cases have been reported. CASE: A 37-year-old woman presented with a rapidly growing breast mass. Mammography showed a huge, well-circumscribed cystic mass (17 x 16 x 16 cm) suggestive of a benign lesion. Cytologic examination revealed a highly cellular tumor composed of malignant cells of various sizes and shapes in a necrotic background. The smears were diagnosed as positive for malignancy and suggested metaplastic carcinoma. Mastectomy was performed, and histologic study confirmed the cytologic diagnosis. CONCLUSION: This is the first reported case of a breast cyst of this size. Clinically the cyst was confused with a benign lesion. The fine needle aspiration aided the diagnosis and planning of treatment.     

Risk factors for postpartum ovarian cysts and their spontaneous recovery or persistence in lactating dairy cows

Cystic ovarian disease is a major cause of reproductive failure and economic loss for the dairy industry. Many cysts that develop during the early postpartum period regress spontaneously. However, it is difficult to decide at what point it would be more cost effective to treat ovarian cysts than to wait for spontaneous recovery. The objective of this study was to analyze risk factors for the development of the ovarian cystic condition during early and late postpartum, and for its persistence or recovery during the pre-service period in lactating dairy cows. Using multiple logistic regression, we analyzed data derived from 873 lactating dairy cows from a single herd. An ovarian cyst was diagnosed if it was possible to observe a single follicular structure with an antrum diameter > or = 25 mm in the absence of a corpus luteum in three sonograms performed at 7-day intervals. The cystic condition was denoted as early if the cyst was diagnosed 43-49 days postpartum, and late if detected 57-63-day postpartum. Spontaneous cyst regression before 60-day postpartum was regarded as early cystic recovery. For the early cystic group, there were no significant effects of lactation number, body condition score on prepartum Day 60, at parturition or on postpartum Day 30, or of body condition loss from parturition to 30-day postpartum. Cows calving in summer were 2.6 times more likely to develop ovarian cysts than those giving birth in winter. The risk of having a cyst was 1.9 times higher in cows with an abnormal puerperium. A 1-kg increase in milk yield raised the risk of cysts by a factor of 1.05. A 1-unit increase in body condition score (scale from 1 to 5) from prepartum Day 60 to parturition increased the risk of cyst development 8.4 times. Milk production and lactation number were negatively correlated with spontaneous early cyst recovery. A 1-kg decrease in milk production increased the probability of cyst recovery by a factor of 1.06, and a 1-unit drop in lactation number was associated with a 1.4-fold increased probability of cyst recovery. For the late cystic group, there were no significant effects of abnormal puerperium and body score data, except for a prepartum change in body score. Calving season (Odds ratio: 2.3), lactation number (Odds ratio: 1.36), increased milk production (Odds ratio: 1.05) and increased body condition score during the prepartum period (Odds ratio: 4.3) were all related to an increased risk of ovarian cysts. The probability of having a late cyst was 36.6 times greater in cows with early cysts. These findings suggest that it would be profitable to treat multiparous cows having cysts very early in the postpartum period, while treatment of primiparous cows should be delayed, at least until the end of the pre-service period, to provide the opportunity for spontaneous recovery.     

Ultrastructural observations of previtellogenic ovarian follicles of dove

Dove ovarian follicle is a complex structure composed of oocyte surrounded by a somatic compartment consisting of theca externa, theca interna and granulosa. The structure of ovarian follicle (1 and 2 mm) of dove was studied by electron microscopy. The granulosa was pseudostratified in the 1-mm-diameter follicles and stratified with two or three irregular rows of cells in the 2-mm-diameter follicles. In the larger follicle indentations between oocyte and granulosa cells become more numerous and the microvilli of granulosa cell elongated to form a zona radiata with similarly elongated oocyte microvilli. Lining bodies were present at the tips of granulosa microvilli and in the cortical region of the oocyte. In the oocyte cortex were observed coated pits, coated vesicles, dense tubules, multivesicular bodies and primordial yolk spheres. Primordial yolk spheres may contain lining bodies and were observed fused with dense tubules and multivesicular bodies or associated with smooth cisternae.     

Levels of heat shock protein transcripts in normal follicles and ovarian follicular cysts

In the study, the gene expression of several heat shock proteins (HSPs) was determined in normal follicles and cystic follicles from cattle. A lower expression of HSP10 and HSP40 was observed in granulosa and theca cells of cysts compared to normal follicles. HSP27 was significantly less expressed in granulosa cells in cystic and large antral follicles than in other follicular categories. HSP60 and HSP90a expressions were highest in theca cells of cysts. However, HSP70 and HSP90b exhibited a lower expression in cysts than in healthy follicles.     

Gonadotropin releasing hormone treatment of dairy cows with ovarian cysts. I. Gross ovarian morphology and endocrinology

Dairy cows diagnosed as having ovarian cysts were assigned to receive either sterile water or 100 mug GnRH (5 cows/group). Immediately prior to treatment and three days post-treatment, ovaries were observed via paralumbar laparotomy, photographed and visible structures and ovarian size recorded. Nine to thirteen days post-treatment, ovaries were removed. Blood plasma was collected for hormone determinations prior to each surgery, 1.5 and 3.0 hours and 1, 5 and 9 days post-treatment. Although concentrations were similar between groups prior to treatment, concentrations of progesterone were higher and LH and estradiol-17beta lower for GnRH treated cows than control cows, immediately prior to ovariectomy. A layer of luteal tissue approximately 5 mm thick was present around the periphery of the cystic structure at ovariectomy in 4 of 5 GnRH treated cows, but in only one control cow. The thickness of the luteal layer around the periphery of the ovarian cysts was correlated -.82, .78 and -.63 with estradiol-17beta, progesterone and LH, respectively. In summary, response to GnRH treatment in cows with ovarian cysts appears to be characterized in most cases by luteinization of the cystic structures.     

Comparison of biochemical markers between benign and malignant ovarian cysts

To investigate the presumption that earlier diagnosis of ovarian tumors might lead to an improved outcome, we compared several substances in the fluid of benign and malignant ovarian cysts. Our results showed the following: (1) benign cysts were readily separated from malignant cysts on the basis of total lactate dehydrogenase (LD) activity and except for mucinous cysts, by their isoenzyme patterns. (2) Preoperative serum total LD activity and LD isoenzymes were of no diagnostic help in predicting the malignant tumors. (3) Carcinoembryonic antigen (CEA) levels usually differed greatly between benign and malignant cysts, although the benign mucinous cysts had CEA levels indistinguishable from malignant cysts. (4) Prominent quantitative differences between Roche and Abbott CEA activity were present in both benign and malignant cysts. (5) Preoperative serum CEA levels were not helpful in differentiating the benign from the malignant cysts.     

mRNA expression pattern of gonadotropin receptors in bovine follicular cysts

Follicular growth and steroidogenesis are dependent on gonadotropin binding to their receptors in granulosa and theca cells of ovarian follicles. The aim of the present study was to evaluate the expression patterns of follicle-stimulating hormone receptor (FSHR) and luteinizing hormone receptor (LHCGR) in ovarian follicular structures from cows with cystic ovarian disease (COD) as compared with those of regularly cycling cows. Relative real-time RT-PCR analysis showed that the expression of FSHR mRNA in granulosa cells was highest in small antral follicles, then decreased significantly as follicles increased in size, and was lowest in cysts. FSHR mRNA was not detected in the theca cells of any follicular category, including cysts. LHCGR mRNA expression in granulosa cells was significantly higher in large antral follicles than in cysts, and not detected in granulosa cells of small and medium antral follicles. In theca cells, the expression level of LHCGR mRNA in medium antral follicles was higher than in small and large antral follicles, whereas that in follicular cysts it was similar to those in small and medium antral follicles, but higher than that in large antral follicles. Our findings provide evidence that there is an altered gonadotropin receptor expression in bovine cystic follicles, and suggest that in conditions characterized by altered ovulation, such as COD, changes in the signaling system of gonadotropins may play a fundamental role in their pathogenesis.     

Intrafollicular steroids and anti-mullerian hormone during normal and cystic ovarian follicular development in the cow

Development of follicular cysts is a frequent ovarian dysfunction in cattle. Functional changes that precede cyst formation are unknown, but a role for anti-Müllerian hormone (AMH) in the development of follicular cysts has been suggested in humans. This study aimed to characterize intrafollicular steroids and AMH during follicular growth in a strain of beef cows exhibiting a high incidence of occurrence of follicular cysts. Normal follicular growth and cyst development were assessed by ovarian ultrasonography scanning during the 8 days before slaughtering. Experimental regression of cysts was followed by rapid growth of follicles that reached the size of cysts within 3-5 days. These young cysts exhibited higher intrafollicular concentrations of testosterone, estradiol-17beta, and progesterone than large early dominant follicles did in normal ovaries, but they exhibited similar concentrations of AMH. Later-stage cysts were characterized by hypertrophy of theca interna cells, high intrafollicular progesterone concentration, and high steroidogenic acute regulatory protein mRNA expression in granulosa cells. Progesterone and AMH concentrations in the largest follicles (> or =10 mm) and cysts were negatively correlated (r = -0.45, P < 0.01). Smaller follicles (<10 mm) exhibited higher intrafollicular testosterone and estradiol-17beta concentrations in ovaries with cysts compared to normal ovaries. During follicular growth, AMH concentration dropped in follicles larger than 5 mm in diameter and in a similar way in ovaries with and without cysts. In conclusion, enhanced growth and steroidogenesis in antral follicles <10 mm preceded cyst formation in cow ovaries. Intrafollicular AMH was not a marker of cystic development in the cow, but low AMH concentrations in cysts were associated with luteinization.