Displaced granulosa cells in the fallopian tube mimicking small cell carcinoma

Fallopian Tube Neoplasia and Mimics

This review discusses select fallopian tube entities and their associated mimics. It first focuses on adenomatoid tumors, the most common benign tumor of the fallopian tube. High-grade serous carcinoma and its precursor, serous tubal intraepithelial carcinoma, are then addressed. Finally, attention is turned to endometrioid proliferations of the fallopian tube. A diagnostic approach is provided for these lesions, with an emphasis on differential diagnoses and situations in which a benign lesion may appear malignant, and vice-versa.

Incidental Microscopic Granulosa Cell Proliferations: Tumorlet or Non-neoplastic?

Microscopic granulosa cell proliferations are rare incidental findings in ovarian and extraovarian tissue, and can simulate granulosa cell tumors. We report a case of a 22-yr-old nulliparous woman with incidental microscopic granulosa cell proliferation in the wall of an endometriotic cyst. Excision of the cyst revealed extensive endometriosis and incidental microscopic nests and cords of granulosa cells measuring 1.5 mm and positive for inhibin A and calretinin. A rare Call-Exner body was noted. An extensive literature review of both ovarian and extraovarian granulosa cell proliferations were performed to determine their possible origin, variable morphologic features and differential diagnosis. Forty-seven cases were identified occurring in pregnant (26%) and nonpregnant (74%) settings. The nonpregnant cases reveal an association with endometriosis and endometrioid adenocarcinomas. Follow-up data is very limited, but no reports of subsequent granulosa cell tumors are reported. We hypothesize that possible anovulation may play a role in the development of these proliferations. Because of unknown pathogenesis and limited follow-up data being available, their clinical significance and risk of neoplasia remain unclear.

Microscopic Heterotopic Extraovarian Sex Cord-Stromal Proliferations: Expanding the Histologic Spectrum

Microscopic, heterotopic extraovarian sex cord-stromal proliferations have only recently been reported in the literature. We describe the largest series to date, of 30 cases of microscopic, incidentally detected, heterotopic extraovarian sex cord-stromal proliferation, in women aged 25-79 yr who had undergone surgery for a range of benign and malignant gynecologic conditions. In 14 patients the foci of proliferation comprised ovarian cortical stroma, in some cases with an ovarian fibroma-like appearance. Ten cases of adenofibroma and cystadenofibroma were also identified, including 1 Brenner adenofibroma; 2 cases comprised both ovarian cortical stroma and serous cystadenofibroma; 4 cases showed sex cord proliferation resembling microscopic adult granulosa cell tumors. Immunohistochemistry, where possible, confirmed the sex cord nature of the heterotopic proliferations. The foci of proliferation were <1-7 mm, and most were at the fimbrial end of the fallopian tube. These proliferations are likely to be encountered with increasing frequency as we sample the adnexa more extensively. Previous reports postulated that the proliferations probably represent embryonic rests caused by anomalous migration but we suggest that incorporation of exposed ovarian parenchymal tissue into the fimbrial stroma at the time of ovulation may be another possible cause.

Generation of multi-oocyte follicles in the peripubertal rat ovary: link to the invasive capacity of granulosa cells?

OBJECTIVE

To assess the presence and numbers of multi-oocyte follicles (MOFs) in the rat ovary at different stages of postnatal maturation.

DESIGN

Animal (rat) study.

SETTING

Research laboratory.

ANIMAL(S)

Female Wistar rats.

INTERVENTION(S)

Histologic/morphometric analyses in ovaries from infantile, juvenile, pubertal, and adult female rats.

MAIN OUTCOME MEASURE(S)

Numbers and characteristics of MOFs in rat ovaries at different stages of postnatal maturation.

RESULT(S)

Female rats displayed low numbers (<5/ovary) of MOFs in the infantile period (postnatal day [PND] 15). The occurrence of MOFs increased sharply by PND-21 and remained at high values (>15/ovary) up to PND-60, to decline thereafter by PND-90. The presence of irregularly shaped and connected adjacent follicles, together with the identification of ruptures at the follicle surface and the occasional invasion of the ovarian stroma by granulosa cells, strongly suggests that the majority of MOFs in peripubertal rats are generated by fusion of adjacent growing follicles.

CONCLUSION(S)

A new mechanism for the generation of MOFs linked to the potential invasive capacity of granulosa cells is proposed. The basis for the upsurge in the generation of MOFs during the peripubertal period and whether, as predictable, this phenomenon is applicable to other mammalian species warrant further investigation.