Cytopathological features of scar endometriosis mimicking an adenocarcinoma: A diagnostic pitfall
This was a case report of a 33-year-old, non-obese, Asian, lady physician, P1, A0 sustained a minor scald over her right inguinal region. The scald was adjacent, but not involving the right lateral aspect of her 3-year-old Pfannenstiel incision scar. The wound completely re-epithelialized within 10 days, leaving behind slight skin discoloration. A month later, she noticed a “thumb-sized” swelling in the same area. She had a normal menstrual history.\nClinically, the swelling was superficial to abdominal muscles and measured 2 cm; was non-tender, non-inflammatory, firm and mobile. She underwent FNAC, followed by incisional biopsy and excision.\nThe patients’ serum tumor marker levels, including celomic antigen (CA) 125, carcino embryogenic antigen and CA 19.9 were within the normal range.\nHer abdominal and pelvic ultrasonogram revealed a 3 cm sized subcutaneous, hypoechoic, solid mass with scattered internal echoes.\nMagnetic resonance imaging (MRI) showed a heterogeneous subcutaneous soft tissue mass measuring 3 cm × 2.5 cm × 2 cm. The lesion was hypointense on plain T1-weighed images, hyperintense on T2-weighed and short inversion time recovery axial images. Post-contrast T1-weighed images showed heterogeneous enhancement within the lesion [].\nOn review, Hematoxylin and Eosin (H and E), as well as Giemsa stained smears were hypercellular and revealed epithelial cells in groups and glandular architecture, imperceptibly admixed with numerous, relatively smaller, short spindly cells. Epithelial cells exhibited mild to focally, moderate nuclear enlargement. Interspersed were metaplastic cells against a hemorrhagic background []. Whereas the initial diagnosis offered was a metastatic adenocarcinoma, on review, endometriosis was suggested.\nIncisional biopsy revealed fibrocollagenous tissue and few glands exhibiting focal nuclear atypia that was interpreted as dysplasia.\nExcision specimen measured 5.5 cm × 4.5 cm × 2.5 cm with an overlying skin that showed a linear scar. On serial sectioning, a firm nodule was identified in the subcutaneous region measuring 1.3 cm × 0.5 cm × 0.4 cm. Cut surface of the nodule was grey-white with focal areas of hemorrhage.\nConventional H and E stained microsections showed glandular structures, exhibiting focal dilatation, surrounded by stromal cells, indicative of endometrial tissue with focal inflammation and metaplasia. Epithelial cells exhibited focal atypia. However, there was insufficient atypia to label it as an adenocarcinoma. Diagnosis of endometriosis was offered. Immunohistochemically, the glands were diffusely positive for estrogen receptor and progesterone receptor while the stroma was diffusely positive for CD10. Diagnosis of endometriosis was reinforced []. All the resection margins were free of the lesion.\nPost-surgery, patient is on gonadotropin releasing hormone analogues; is currently free of disease since 12 months and is on follow-up.