Intraoperative scrape cytology: Adult granulosa cell tumor of ovary.

Adult granulosa cell tumor is often a hormonally active stromal cell neoplasm of the ovary with malignant potential. Intra-operative pathological assessment is a valuable tool in guiding optimal surgical treatment in patients. Of the various intra-operative cytological diagnostic modalities, scrape smear cytology is an effective, economical, simple, fast and reliable method with results comparable with frozen section diagnosis. We describe a case of adult granulosa cell tumor in a 30-years-old lady diagnosed on intra-operative scrape cytology, and further reconfirmed on frozen section and histopathology.

Introduction

Ovarian neoplasms are a heterogenous group of benign and malignant tumors of epithelial, stromal and germ-cell origin. Intra-operative cytological interpretation of these tumors is both interesting and challenging. Granulosa cell tumors (GCT) account for 1.5% of all ovarian tumors and about 5-8% of all ovarian malignancies. Approximately 95% of GCT cases occur in adults, and these are prone to develop recurrence which occasionally happens may years after the initial diagnosis.[12] Many studies have established the criteria for cytological diagnosis of ovarian tumors including GCTs.[23]

Fine needle aspiration cytology (FNAC) as a pre-operative investigation for ovarian neoplasms has been discouraged to reduce the risk of possible intra-peritoneal seeding.[4] For effective planning of the surgical management, the demand for intra-operative cytological assessment has increased in recent years in patients with suspected ovarian neoplasms.[5-7] In this report, we describe a case of adult tumor GCT, where intra-operative cytology, not only helped in obtaining a diagnosis but also helped in planning the surgical protocol.

Case Report

A 30-years-old lady (P2L2) with last childbirth 7 years back presented with amenorrhea and anorexia of 1-year duration. She denied any history of abdomen pain, weight loss, chronic cough or fever. Her menstrual history was normal prior to onset of symptoms. On examination, she was found to have a mobile, non-tender lump in the suprapubic region. Gynecological evaluation revealed a healthy cervix with retroverted uterus. A mass of 22-24 weeks size pregnancy was felt separately from the uterus in the anterior fornix. Groove's sign was positive.

Routine investigations were within normal limits. Serum CA-125, alpha-fetoprotein, carcino-embryonic antigen and β-human chorionic gonadotrophin levels were normal. Ultrasonography of the pelvic region revealed a complex left adnexal mass measuring 12.7 × 9 × 11.6 cm with central solid and cystic areas with calcification. Computerized tomography scan of the abdomen was suggestive of a neoplastic lesion of the left ovary, with a differential diagnosis of teratoma and ovarian carcinoma. The patient was taken up for staging laparotomy. Intra-operatively, resected ovarian tumor was sent for pathological examination. On macrosopy, the tumor measured 18 × 11 × 8 cm in size, encapsulated with a smooth external surface. The cut surface was solid with small cystic spaces and yellowish in appearance. Scrape smears were prepared and the specimen was also processed for frozen section.

On microscopy, the smears were hypercellular with cells arranged in a follicular and trabecular pattern. The cells were also seen dispersed in loose cohesive sheets with focal tight micro-follicular pattern occasionally traversed by delicate vasculature. Individual tumor cells were small to moderate sized, round to oval with occasional large cells having high nuclear: cytoplasmic ratio. The cytoplasm was delicate, with occasional fine vacuoles. The nuclei were central, round to oval with fine, evenly distributed chromatin and with occasional prominent nucleoli. Focally nuclear grooves were also noted. Wisps of metachromatic stroma in between tumor cells and cellular follicular arrangements reminiscent of Call-Exner bodies with central metachromatic stroma were present [Figure 1a–d].

Figure 1

(a) Photomicrograph of cytology smears showing a hypercellular smear with cells in a trabecular pattern (MGG, ×40), (b and c) and also in loose cohesive sheets with focal tight micro-follicular pattern. Focally cellular follicular arrangement reminiscent of Call-Exner bodies with central metachromatic stroma (MGG, ×100). (d) Occasional large tumor cells with fine vacuolated cytoplasm and high nuclear: cytoplasmic ratio. The nuclei were central, round to oval with fine, evenly distributed chromatin with occasional prominent nucleoli (→) and nuclear grooves (-->). (MGG, ×400). (e) Frozen section (Toluidine blue, ×100) and (f) formalin-fixed paraffin embedded section (H and E, ×100)

A diagnosis of GCT was offered, which corroborated with frozen section examination [Figure 1e].

The patient underwent right-sided oophorectomy with bilateral lymph node dissection. The contralateral ovary was preserved.

Subsequent formalin-fixed paraffin-embedded (FFPE) sections confirmed the above findings and diagnosis of GCT [Figure 1f].

Discussion

FNAC is a simple and reliable method for the diagnosis of a variety of female genital tract tumors. However, till date the gynecologists across the world are hesitant to accept the role of preoperative FNAC on pelvic masses, especially in ovarian masses, owing to the potential risk of intra-peritoneal tumor implantation, though the risk is often overestimated and has not been conclusively documented.[3]

Intra-operative diagnosis of ovarian lesions can be achieved by a number of cytological techniques, including imprint and scrape cytology, and intra-operative fine-needle aspiration cytology. Though these methods are less accurate as compared to frozen sections, these are bereft of the fear of dissemination and also has an added advantage of providing a more specific diagnosis in most cases.[57] However, few studies have demonstrated that in experienced hands the diagnostic efficacy of intra-operative cytology are comparable to that of frozen sections with 92% diagnostic accuracy in characterizing cytological pattern and morphology of ovarian tumors.[910]

Scrape smear cytology is a modification of imprint cytology in which cells are harvested by scraping the cut surface of the specimen. It is an economical, simple and quick method of intra-operative diagnosis, and does not alter the utility of the specimen for subsequent histopathology examination.[56] Though the history of scrape cytology dates back to 1927, its utility during intra-operative consultation has often been neglected in comparison to frozen sections and imprint cytology. Scrape cytology could be preferred over touch preparation/imprint cytology, as in most cases, the former technique would yield much more material than the latter. Further, its role as a potential tool in intra-operative consultation is more pertinent in institutions unequipped with frozen section facility.[10] In these scenarios, in experienced hands, it not only offers a viable alternative, but also helps to reduce the overall cost and processing time, without compromising quality.

Nuclear features, seen in GCT, along with nuclear grooves may also be seen in proliferating Brenner tumor and sex cord tumor with annular tubules (SCTAT).[11] Immunostaining with beta-inhibin, CD99, vimentin and cytokeratin is confirmatory of GCT. Other corroborative molecular genetic markers include somatic FOXL2 402C>G mutation, and conditional disruption in the PTEN mutation in the Kras (G12D), expressing granulosa cells.[1213]

Rapid intra-operative diagnosis of the nature of ovarian tumors in a young woman avoids unnecessary removal of contralateral ovary and helps preserve fertility. It can allow individualization of treatment like complete surgery in a case of malignancy and particularly the post-operative irradiation of anaplastic carcinoma. It can also be used for staging, for post-operative follow-up, and for recurrences. Material obtained by this technique can be utilized for flow cytometry and cytogenetic studies. In spite of the various applications, its use has not been widely recognized in diagnosis of ovarian tumors and there are only a few reports on diagnosis of ovarian tumors, including GCTs, by imprint cytology. The case reiterates the accuracy of scrape cytology in intra-operative ovarian tumor diagnosis by correlating it with histopathology which is considered as the gold standard.[23]

Conclusion

Cytological evaluation provides a better morphological detail, and in experienced setup compares well with frozen section and subsequent formalin-fixed paraffin-embedded sections. Ability of the scrape cytology smears to render immediate diagnosis highlights its role and potential usage in intra-operative consultation in institutions unequipped with frozen section facility.