Role of imprint cytology in intra-operative diagnosis of an unusual variant of teratoma.

Sir,

Benign cystic teratoma is a common ovarian neoplasm of germ cell origin occurring in the reproductive age group. Usually there is no difficulty in macroscopic diagnosis of this benign tumor as most of the tumors show a unilocular cyst filled with sebaceous material or hair. But sometimes there is a diagnostic difficulty when the tumors have a solid or multilocular appearance. Imprint cytology has proved to be an adjunct to histopathology in early diagnosis of ovarian tumors preoperatively.[1] We report a case of mature solid multilocular teratoma diagnosed by imprint cytology in the operation theatre which clinically was a diagnostic dilemma.

The case was an 18-year-old girl who presented with abdominal pain of 2 months duration and abdominal mass of 1 month duration. Computed tomography (CT) scan showed 16 × 15 × 11 cm mixed multiloculated mass lesion in pelvis on the right side with areas of soft tissue component in it. Thinking of a diagnosis of germ cell tumor which is common in this age group biochemical markers were done. CA-125 was slightly elevated (43.1 U/mL). Other markers – AFP, LDH, CEA, and β HCG – were within normal limits. Clinical diagnosis was an ovarian malignancy. At the time of surgery the cytopathologist was called upon to take imprint cytology of the ovariotomy specimen so that the surgeons could change the surgical plan depending on behavior of the tumor.

Grossly the ovary weighed about 1 kg and measured 18 × 11 × 6 cm. The surface was smooth, whitish, bosselated with congested vessels. The cut section showed multiple small cysts with honey comb-like pattern filled with whitish to yellowish mucoid material [Figure 1a]. Imprint cytology smears were taken and stained with Field's and H and E stains.

Figure 1

(a) Gross specimen showing a multilocular, honey comb-like pattern, (b) Strip of mucinous epithelium (H and E, ×400), (c) Strip of respiratory epithelium (Field's stain, ×1000), (d) Multiple cystic spaces lined by mucinous epithelium (H and E, ×200)

Cytology smears showed epithelial cell clusters in a background of abundant mucinous material and scattered cells with intracytoplasmic mucin and many signet ring cells. The possibility of a mucinous neoplasm was initially considered. But a meticulous search showed strips of respiratory and mucinous epithelium and collections of mature squamous cells [Figure 1b and c]. Gross appearance was highly suspicious of an immature teratoma. But even with extensive search immature elements could not be identified. With this picture we gave a diagnosis of a benign cystic teratoma. No further intervention was done and the surgery was stopped short with an ovariotomy.

Histopathology slides showed multiple cystic spaces lined by mucinous epithelium of endocervical and intestinal type [Figure 1d], squamous epithelium and pseudostratified columnar epithelium with focal squamous metaplasia. Nests of mature cartilage were also seen. Multiple sampling did not show immature or neuroepithelial tissue. The mucinous epithelium was seen adjacent to the squamous epithelium. There was no separate mucinous cystadenoma component. So the possibility of a mature cystic teratoma co-existing with mucinous cystadenoma could be ruled out. All these findings confirmed a diagnosis of benign cystic teratoma.

Benign cystic teratoma commonly occurs as a unilocular cyst and rarely as a multilocular multicystic tumor. A cystic teratoma with predominant mucinous component is very rare.

Importance of imprint cytology in intra-operative diagnosis has been proven in many studies. Imprint cytology can be used as a substitute in centers where facilities for frozen section is not available[1] or imprint cytology can be combined with frozen sections to increase accuracy in rapid tissue diagnosis.[2] It is a simple and efficient way to diagnose ovarian neoplasms at the time of surgery which will help the surgeons to take important decisions regarding the optimal extent of surgery.