Sex cord stromal tumours of the ovary, experience at Shifa International Hospital Islamabad.

This descriptive study was carried out at Pathology Department, Shifa International Hospital from 2007 to 2016; all sex cord stromal tumours diagnosed during this time period were included. Epithelial, germ cell and metastatic tumours were excluded from the study. A total of 1254 Ovarian tumours were brought to Shifa of which47 (4%) were labeled as sex cord stromal tumours. Of these 36( 76 %)were granulosa cell tumour (adult33, juvenile3), 7 were labeled as sertoli leydig cell tumours (15%), 3 as thecoma/ fibroma group (7%)and only one case was labeled as microcystic stromal tumour of the ovary (2%). Overall age range for sex cord stromal tumours was 42 (12-71). Immunohistochemistry was done in 41 out of 47 cases. Sex cord stromal tumours of the ovary are rare tumours comprising 4% of the total. Adult Granulosa cell tumour is the commonest tumour seen in our study.

Cutaneous involvement in luteinized thecomas with sclerosing peritonitis (LTSP)-A new finding in a rare syndrome.

Luteinized thecomas with sclerosing peritonitis (LTSP) is a rare disease characterized by ovarian luteinized thecomas and associated fibrosing peritonitis. Cutaneous involvement has never been reported. We report a case of classical LTSP with skin involvement, outlining the clinical and histopathologic features of this novel presentation of a rare syndrome.

FDG-PET-positive ovarian thecoma with GLUT5 expression: Five cases.

Positron emission tomography (PET) with fluorodeoxyglucose F18 (18 F-FDG) is useful for detecting malignancies, but benign lesions occasionally have false-positive 18 F-FDG uptake. Here, we report the cases of five postmenopausal women with solid ovarian tumors suspected to be ovarian cancer on magnetic resonance imaging and 18 F-FDG uptake. Mean age of the five patients was 57 years (range, 53-65 years). Average early standardized uptake value (SUV) of 18 F-FDG was 5.76 (range, 2.2-12.0) and delayed SUV was 6.56 (range, 2.4-13.8). In all five patients, frozen section diagnosis at surgery was thecoma, and bilateral salpingo-oophorectomy was performed. On immunohistochemistry, immunoreactive glucose transporter 5 (GLUT5) expression was detected in thecoma tissues. This case shows that thecoma sometimes has positive 18 F-FDG uptake on positron emission tomography-computed tomography (PET-CT), indicating the need for caution regarding false-positive PET-CT in patients with benign solid ovarian tumor.

Ovarian thecoma-fibroma groups: clinical and sonographic features with pathological comparison.

BACKGROUND: Ovarian thecoma-fibroma groups (OTFG) are uncommon sex cord-stromal neoplasms. The objective of the study was to demonstrate clinical and sonographic features of OTFG and compare with surgical histopathology. METHODS: A total of 61 patients with surgically proven OTFG were enrolled in this retrospective study to demonstrate its clinical and sonographic features and to compare with pathological findings. Gray scale and color Doppler sonography were performed presurgically with either transabdominal or transvaginal approach to image pelvic structures and lesions. The clinical findings and sonographic appearances were compared with the types of the OTFG tumors based on the histopathological diagnosis. RESULTS: The mean patient age was 53.57 (range, 26-86) years. There were 63.93% (39/61) patients in postmenopausal and 63.93% (39/61) patients with no clinical symptoms. Ultrasound findings of OTFG revealed as solid tumors with a typical feature of well-demarcated hypoechoic masses in 70.49% (43/61), among which 74.41% (32/43) tumors were smaller than 5 cm in diameter. There were 17 mixed echogenic masses with calcification, hemorrhage, or cyst, among which 70.59% (12/17) lesions were larger than 5 cm in diameter. Acoustic attenuation of the tumor was presented in 44.26% (27/61) of the cases. Doppler flow signals within the tumors were found in 20 cases (32.79%), in which 80% (16/20) had minimal or moderate flow signals. Ascites was detected in 32.79% (20/61) of the cases, Megi's syndrome was found in 1 case. Final pathology revealed 41 (67.21%) thecoma-fibromas, 15 (24.59%) fibromas, 4 (6.56%) thecomas and 1 (1.64%) fibrosarcoma. There were 58 patients underwent cancer antigen 125 (CA125) test, and 20.69% (12/58) showed an elevated level. The diameter of tumors was found to be significantly correlated with CA125 level (p < 0.01) and the amount of ascites fluid (p < 0.05). CONCLUSIONS: The typical sonographic features of OTFG include adnexal hypoechoic masses with clear border and acoustic attenuation as well as minimal Doppler flow signals. All the aforementioned features could make ultrasound imaging as a assistent tool improve the preoperative diagnostic accuracy.

Inhibin A and inhibin B producing ovarian fibrothecoma revealed by suppression of follicle stimulating hormone (FSH) in a post-menopausal woman: report of the first case.

In this report, we describe the first case ever reported in the literature, of an inhibin-A (INHA) and inhibin-B (INHB) producing fibrothecoma. A post-menopausal woman was referred to our unit because of follicle stimulating hormone (FSH) level below the reference interval for postmenopausal women. By contrast luteinizing hormone, hCG, and estradiol levels were within normal range. This discrepancy suggested the secretion of FSH inhibitory factors. INHB and INHA levels were markedly elevated for age, 475 pg/mL and 100 pg/mL, respectively. Ultrasonography and MRI showed a pelvic mass of indeterminate nature. Abnormal inhibin secretion is generally observed in granulosa cell tumors. In this case this etiology was unlikely because of low estradiol and AMH levels. Surgical exploration revealed a 10 cm mass of the left ovary proven histologically to be an ovarian fibrothecoma (OFT). After tumor removal, INHB and INHA levels decreased rapidly. Only three cases of OFT with an important secretion of INHB have been reported to date. INHA secretion has never been associated with OFT. There is a need to develop coupled hormone and imaging strategies to diagnose the source of INH secretion in case of FSH/LH discrepancy.

Hypoxia is important in F­18 FDG accumulation in thecoma­fibroma tumors on F­18 FDG PET/CT scans.

Several studies have noted benign thecoma­fibroma tumors with positive F­18 fluorodeoxyglucose (FDG) accumulation mimicking malignant ovarian tumors following F­18 FDG positron emission tomography (PET). The present study analyzed four cases with false­positive F­18 FDG PET/computed tomography (CT) diagnoses of thecoma­fibroma tumors as malignant tumors due to F­18 FDG accumulation, compared with eight cases of FDG­positive ovarian cancers and two cases of FDG­negative fibromas. Hypoxia inducible factor (HIF)­1α expression was examined in the six thecoma­fibroma tumors using reverse transcription­polymerase chain reaction (RT­PCR). The four F­18 FDG­positive cases exhibited higher cellularity, maximum standard uptake and signal intensity on T2­weighted imaging, and gadolinium (Gd) enhancement using magnetic resonance imaging than the two FDG-negative fibroma cases. In the F­18 FDG­positive thecoma­fibroma group, Ki­67 expression was low and LAT1 expression was not identified, ruling out the diagnosis and potential for malignancy. However, considerable glucose transporter 1, HIF­1α, and vascular endothelial growth factor expression was observed. HIF­1α expression was elevated in all four false­positive cases by RT­PCR. From these results, it was hypothesized that hypoxia due to elevated cellularity may stimulate HIF­1α expression and be associated with F­18 FDG accumulation in F­18­positive thecoma­fibroma tumors.

Recurrent endometrial hyperplasia as a presentation of estrogen-secreting thecoma - case report and minireview of the literature.

Thecoma is a rare ovarian tumor, presenting usually in postmenopausal women as unilateral, benign, solid lesion. About 15% of affected patients develop endometrial hyperplasia (EH) and 20% are diagnosed with endometrial cancer. In this case report, we present 60-year-old women admitted because of recurrent spotting of 5 years duration, which started 1 year after menopause. In history, the patient underwent three times curettage procedures and once (1 year before admission) had estradiol levels typical for reproductive-age women. At admission, we found elevated serum levels of estradiol (222.5 pg/ml) and a small mass in the right ovary. The markers of germ cell tumors were negative. After the initial diagnosis, the patient was qualified for total abdominal hysterectomy with bilateral salpingo-oophorectomy. The histopathological examination and immunohistochemical staining confirmed the thecoma diagnosis. In follow-up examination after 8 weeks, we found decreased serum estradiol levels and relief of the symptoms. In conclusion, we want to underline that in cases of EH, especially in patients with a history of recurrences, the special attention should be paid for differential diagnosis. In such cases, the estrogen-secreting tumors should be excluded.

MRI diagnosis of ovarian fibrothecomas: tumour appearances and oestrogenic effect features.

OBJECTIVE: To study MRI diagnosis of ovarian fibrothecomas. METHODS: MRI appearances of 27 ovarian fibrothecomas 26 female patients confirmed by surgical pathology were retrospectively reviewed and correlated with clinical and histological findings. RESULTS: Most patients were post-menopausal females 73.1% (19/26) of cases. 38.5% (10/26) of patients showed an elevated serum carbohydrate antigen 125 (CA-125) level (>35 U ml(-1)). On MR T2 weighted imaging, 3 distinct features were revealed. (1) Homogeneous hypointense masses in 25.9% (7/27) cases. (2) Heterogeneous tumours with mostly isointense and few patchy hyperintense areas in 51.9% (14/27) cases. (3) Heterogeneous tumours with predominantly hyperintense and few isointense parts in 22.2% (6/27) cases. On T1 weighted imaging, all the fibrothecomas turned out to be homogeneous masses except six cystic degeneration cases. After contrast, 70.4% (19/27) tumours showed homogeneous mild enhancement in all phases. Beyond the tumours, endometrial abnormality and uterus enlargement were found in 38.5% (10/26) and 15.4% (4/26) patients, respectively. Ascites were seen in 53.8% (14/26) patients. There was a statistically significant difference among the 3 T2 weighted image features (F = 7.024; p = 0.003) in terms of the size of fibrothecomas. The cystic tumours also had the tendency to show the ascite condition (p = 0.002) as well as elevated serum CA-125 levels (p = 0.014). Vimentin was positively stained in 10 (76.9%) of 13 cases who underwent the immunohistochemical analysis. CONCLUSION: MRI has the superiority to show the distinct appearances of tumours as well as their functional features according to oestrogenic effect. ADVANCES IN KNOWLEDGE: This study describes the unique features of fibrothecomas on MRI on a relatively large series of patients with tumours and the indirect oestrogenic effect findings.

Involuting luteinized thecoma of the ovary.

Spontaneous tumor involution in ovarian stromal tumors is a poorly understood phenomenon. In this report, we describe a rare case of luteinized thecoma that showed extensive involutional changes, such that cellular elements diagnostic of luteinized thecoma were sparse. The convoluted contour of the tumor resembled that observed in a corpus albicans; however, the neoplasm was considerably larger, and the contents of the nodule differed from that of a corpus albicans. The diagnosis of luteinized thecoma was established by the identification of residual aggregates of neoplastic theca cells and a nodule of lutein cells that were positive for inhibin and steroidogenic factor-1. Features of involution within the tumor included a few theca and lutein cells with pyknotic nuclei and abundant cytoplasmic lipid, occasional large adipocytes among the lutein cells, extensive hyalinization, dystrophic calcification, a myxohyaline nodule, and adipose metaplasia. It is likely that some of the aforementioned changes are the result of accompanying ischemia. Cleaved caspase-3 staining patterns were negative within residual lutein and theca cells; thus, we were unable to establish the occurrence of apoptotic bodies.

Fatal case of luteinized thecoma with sclerosing peritonitis in a 40-year-old woman.

We describe the pathologic and clinical presentation of a very rare, fatal case of luteinized thecoma with sclerosing peritonitis in a 40-year-old woman, who had a history of total abdominal hysterectomy and a left salpingo-oophorectomy in 2003. The patient presented with abdominal pain, and radiologic examinations revealed a 10-cm heterogenous right pelvic mass with partial necrosis. The patient eventually underwent an exploratory laparotomy, which revealed an ovarian tumor with multiple implants in the peritoneal cavity. The ovarian lesion was made up of spindle cells among clusters of luteinized stromal cells that expanded to the ovarian cortex. Tumor cells were positive for vimentin, estrogen and progesterone receptors, and CCD68 (focally) and negative for CD34, α-smooth muscle actin, ß-catenin, and desmin by immunohistochemical studies. Luteinized cells were positive for α-inhibin and calretinin. Tumor cells exhibited low Ki-67 proliferation indices. The patient died because of the sclerosing peritonitis component of the disease.

Cellular localization of androgen synthesis in equine granulosa-theca cell tumors: immunohistochemical expression of 17alpha-hydroxylase/17,20-lyase cytochrome P450.

Elevated blood testosterone concentrations, often accompanied by male-typical behaviors, is a common signalment of mares with granulosa-theca cell tumors (GCTCs), but no definitive information exists regarding the cellular differentiation of tumors associated with androgen secretion. This study was conducted to localize and thereby define the cellular expression of 17alpha-hydroxylase/17,20-lyase cytochrome P450 (P450c17), the enzyme most directly responsible for androgen synthesis, in 30 GTCTs and control tissues (gonads and adrenal glands) using immuno-histochemistry (IHC). Immuno-reactivity for P450c17 was evident in approximately half of 30 specimens examined, was most consistent in the interstitial cells surrounding existing or developing cysts, and was less intense in cells within cysts in the smaller proportion of specimens where this was observed. In control tissues, the expression of P450c17 was localized primarily in theca interna of normal ovarian follicles, in theca-lutein cells of some corpora lutea, but not in granulosa-lutein cells. Testicular interstitial cells and islands of adreno-cortical cells located in the adrenal medulla of the adrenal cortex further established the specificity of the antisera used. These data provided the first substantive evidence that polyhedral cells identified previously in GTCTs by histopathology have the potential to synthesize and secrete androgens, similar to theca interna and theca lutein cells in normal equine ovaries.

Intracellular lipid in ovarian thecomas detected by dual-echo chemical shift magnetic resonance imaging: report of 2 cases.

Thecoma of the ovary is a stromal tumor composed of lipid-containing cells with a variable component of fibroblasts. To our knowledge, there have been no reports in the English literature describing detection of intracellular lipid in thecomas by preoperative imaging. We present 2 cases of thecomas of the ovary, in which intratumoral lipid was detected using dual-echo chemical shift magnetic resonance imaging.

Isolated luteinizing hormone (LH) elevation in a woman with secondary amenorrhea: a clue to the diagnosis of an inhibin B-producing thecoma and insights into the influence of inhibin B on LH.

OBJECTIVE: To review the diagnostic possibilities that exists when the workup of amenorrhea reveals an isolated LH elevation; and to examine the effect of inhibin B on LH levels in vivo. DESIGN: Case report. SETTING: University hospital. PATIENT(S): A 20-year-old woman presented with secondary amenorrhea. Her FSH measurement was low, and the LH level was elevated. The recognition that this was an unusual pattern led to the diagnosis of a rare but very treatable inhibin B-producing thecoma, despite the fact that results on the initial pelvic ultrasound examination performed 10 months after presentation of amenorrhea were relatively unremarkable. INTERVENTION(S): Surgical removal of an ovarian thecoma. MAIN OUTCOME MEASURE(S): Gonadotropins, E2, inhibin B, menstrual bleeding, and fertility. RESULT(S): Removal of the ovarian thecoma resulted in a normalization of FSH, LH, and inhibin B levels and a return of spontaneous menses 28 days later. Pregnancy occurred with the third postoperative menstrual cycle, followed by the delivery of a healthy full-term girl. CONCLUSION(S): Inhibin B-producing sex cord granolosa-stromal cell tumors should be considered in women who present with amenorrhea with isolated LH elevations, even in the setting of a previously normal pelvic ultrasound report. Diagnostic considerations that arise in the workup of amenorrhea when there is an isolated elevation in LH that is accompanied by normal or low FSH levels are reviewed. This rare clinical presentation provides the opportunity to observe the impact of inhibin B on gonadotropins in vivo.

Gynecological tumors in Mulibrey nanism and role for RING finger protein TRIM37 in the pathogenesis of ovarian fibrothecomas.

Mulibrey nanism is an autosomal recessive growth disorder caused by mutations in the TRIM37 gene encoding a protein of unknown function. More than half of female patients with Mulibrey nanism develop benign mesenchymal tumors of ovarian sex cord-stromal origin. In this work, we characterize the gynecological tumors of female patients with Mulibrey nanism in detail. In addition to tumors of the fibrothecoma group, 18% (4/22) of the patients were observed with epithelial neoplasias, including 2 ovarian adenofibromas, 1 ovarian poorly differentiated adenocarcinoma and 1 endometrial adenocarcinoma. To investigate the possible involvement of TRIM37 alterations in the pathogenesis of sporadic fibrothecomas, we analyzed the TRIM37 cDNA for mutations and alternatively spliced transcripts and TRIM37 expression in fibrothecomas of women without Mulibrey nanism. No mutations in the open-reading frame of TRIM37 were detected. Two alternatively spliced variants were found, one lacking exon 23 and one exon 2. TRIM37del2 was also found in normal ovary but in a proportion of sporadic fibrothecomas, the TRIM37del2:TRIM37 ratio was increased. In normal ovary, TRIM37 was localized in the cytoplasm of stromal cells, especially theca cells surrounding developing follicles. TRIM37 transcript was found in all sporadic fibrothecomas examined, but 80% (20/25) of the tumors showed reduced or absent expression of TRIM37 protein. Allelic loss at the TRIM37 locus (17q22-23) was observed in 6% of sporadic fibrothecomas. Nearly half of the sporadic fibrothecomas showed evidence of CpG promoter methylation, suggesting promoter downregulation as one mechanism of reduced TRIM37 expression. In conclusion, inherited biallelic inactivation of TRIM37 (Mulibrey nanism) predisposes to both mesenchymal and epithelial ovarian tumors and dysregulation of TRIM37 may also be involved in the pathogenesis of sporadic fibrothecomas.

Luteinized thecomas (thecomatosis) of the type typically associated with sclerosing peritonitis: a clinical, histopathologic, and immunohistochemical analysis of 27 cases.

The nature of the distinctive ovarian lesion often associated with sclerosing peritonitis, initially considered a variant of luteinized thecoma in the paper describing this phenomenon, remains uncertain, as does its long-term prognosis. We describe the features of 27 cases, including immunohistochemical analysis of 13 cases. Sclerosing peritonitis was documented in 25 cases. Patients ranged in age from 10 months to 85 years, and typically presented with abdominal distension and pain with ascites and sometimes bowel obstruction. The ovarian lesions, clinically bilateral in 24 cases, ranged from 2 to 31 cm and often had a striking cerebriform aspect. Microscopically, mitotically active spindle cells with weakly luteinized cells, variable edema, and entrapped follicles were typical. The spindle cells were focally positive with calretinin in 2 cases, CD56 in 2, AE1/3 in 4, smooth muscle actin in 12, and desmin in 8 cases, and negative with alpha-inhibin, epithelial membrane antigen, beta-catenin, CD34, and transforming growth factor-beta, with focal nuclear positivity for estrogen receptor in 5 and progesterone receptor in 11 cases. Luteinized cells were positive with alpha-inhibin, calretinin, and/or CD56. The peritoneal lesions were strongly positive with AE1/3 and exhibited focal weak or moderate positivity with estrogen receptor or progesterone receptor in 4 of 8 cases each. Follow-up in 20 cases (mean: 5.9 y) disclosed no evidence of spread of the ovarian lesion, but 3 patients died of sclerosing peritonitis. The findings fail to allow definitive classification of the ovarian lesions, and we prefer at present to retain their current designation as a subtype of luteinized thecoma, but to allow for the possibility of a non-neoplastic nature, feel it reasonable to have the designation "thecomatosis" as a parenthetical alternative. We have documented for the first time that sclerosing peritonitis is not invariably associated with the distinctive ovarian pathology present in these cases.

The mechanism for protein kinase C inhibition of androgen production and 17alpha-hydroxylase expression in a theca cell tumor model.

INTRODUCTION: In polycystic ovary syndrome (PCOS), there is increased formation of androgens by thecal cells. Moreover, PCOS ovaries have been shown to have decreased levels of c-fos transcription factor. We hypothesize that c-fos expression inhibits 17alpha-hydroxylase 17,20 lyase (CYP17) activity in the human ovary, and its decreased expression seen in PCOS may lead to elevated CYP17 transcription, resulting in increased androgen production. OBJECTIVE: Our objective was to define the role of the activator protein-1 transcription factors, namely c-fos, in the regulation of CYP17 expression in theca cells. METHODS: Human ovarian thecal-like tumor cells were used for all experiments. The following techniques were used: steroid quantification, mRNA extraction, microarray analysis, transfection, small interfering RNA, and immunohistochemistry. RESULTS: Stimulation of human ovarian thecal-like tumor cells with the protein kinase A pathway activator forskolin resulted in stimulation of C19 androgen production. In contrast, treatment with the protein kinase C pathway activator tetradecanoylphorbol acetate (TPA) resulted in decreased androgen production with a shift toward C21 progesterone production. TPA also led to complete inhibition of CYP17. Microarray data showed a 37-fold increase in c-fos after treatment with TPA. Transfection with steroidogenic factor 1 resulted in an increase in CYP17 promoter activity, which was significantly inhibited in the presence of c-fos. c-fos gene silencing led to an increase in CYP17 mRNA levels. Immunohistochemical staining for c-fos in ovaries demonstrated strong staining in granulosa cells, but not theca. CONCLUSIONS: The activator protein-1 transcription factor c-fos plays a role in the inhibition of CYP17 expression. The decreased levels of c-fos expression in polycystic ovaries may be responsible for increased CYP17 levels in PCOS.

Gonadotropin secretion and pituitary responsiveness to GnRH in mares with granulosa-theca cell tumor.

Granulosa-theca cell tumors (GTCTs) are able to secrete variable amounts of sex steroids and immunoreactive inhibin (ir-INH). Although the pituitary appears to be affected by the presence of a GTCT, pituitary responsiveness to exogenous GnRH has not been examined. The aims of the present study were to: (i) assess the plasma hormone concentrations of ir-INH, gonadotropins and sex steroids in eight mares with GTCT and (ii) assess the responsiveness of pituitary gonadotroph cells to exogenous GnRH stimulus both before and after tumor removal. In seven mares, the contralateral ovary was firm, small and inactive. Histopathological observations of the tumors confirmed the presumptive diagnosis of a GTCT. Four mares, judged to be in vernal transition period (n=2) and in the breeding season (n=2), were used as controls. A single intravenous injection of 40 microg of GnRH agonist was given to each mare and blood samples were collected every 15 min from 2 h before to 4 h after injection. In four GTCT mares, this procedure was repeated 20 (n=2) and 90 (n=2) days after tumors removal. All plasma samples were analyzed for concentrations of ir-INH, LH, FSH, estradiol-17beta (E2), testosterone (T) by RIA and progesterone (P) by EIA. Results showed that E2 levels were significantly higher (P<0.001) in control animals compared to E2 levels in GTCT mares before and after surgery. P and T concentrations were not statistically different between the groups. Baseline levels of ir-INH were greater (P<0.05) in GTCT mares before surgery than in control mares, and decreased to undetectable levels after neoplasia ablation. Baseline FSH did not differ between control and GTCT animals either before or after the ovaries were removed. LH baseline values appeared to be higher for affected mares, but the difference was not statistically significant. Maximum release (MR) and area under the gonadotrophin release curve (AUC) after the GnRH challenge for both the gonadotrophins were similar between the groups.

Is loss of heterozygosity at 9q22.3 (PTCH gene) and 19p13.3 (STK11 gene) involved in the pathogenesis of ovarian stromal tumors?

Some ovarian fibromas and rare fibrosarcomas are associated with Gorlin syndrome, which is caused by mutation in the human homologue of Drosophila patched gene (PTCH), localized on chromosome 9q22.3. The relationship between PTCH gene and sporadic ovarian tumors in the thecoma-fibroma group has not been well characterized. On the other hand, we have recently described loss of heterozygosity (LOH) at 19p13.3 in 2 sporadic fibromas with sex-cord elements. We have analyzed DNA from 8 fibromas, 6 cellular fibromas, 2 fibrothecomas, 9 luteinized thecomas, and 2 fibrosarcomas of the ovary for LOH at 9q22.3 and 19p13.3, using polymerase chain reaction amplification for 10 microsatellite markers. LOH at 9q22.3 was detected in 4 (67%) of 6 cellular fibromas, with the highest frequency at microsatellite marker D9S15, which localizes proximal to the PTCH gene. Of 9 luteinized thecomas, 2 (22%) also exhibited LOH at 9q22.3 with 3 microsatellite markers other than D9S15. Allelic losses were not detected in any fibroma, fibrothecoma, or fibrosarcoma. LOH at 19p13.3 was found in 2 (25%) of 8 fibromas, 3 (50%) of 6 cellular fibromas, and 1 (11%) of 9 luteinized thecomas. None of the 2 fibrothecomas or 2 fibrosarcomas showed LOH at 19p13.3. LOH at both 9p22.3 and 19p13.3 was observed in 3 (50%) of 6 cellular fibromas, but not in luteinized thecomas. The results indicate that (1) LOH at both PTCH gene and STK11 gene is relatively frequent in cellular fibromas; (2) approximately a quarter of luteinized thecomas exhibited LOH of the PTCH gene; in both neoplasms, cellular fibromas and luteinized thecomas, LOH may play a role in their pathogenesis; and (3) sporadic cellular fibromas may arise through similar genetic pathways as cases of Gorlin syndrome.