Juvenile sclerosing polycystic adenosis cytologically mimicking Warthin tumor. Issue 11 (22nd July 2019) - Kawai, Masataka
Abstract: Sclerosing polycystic adenosis (SPA) is a rare salivary gland disease. Histologically it resembles a low‐grade ductal carcinoma in situ or sclerosing adenosis of the breast, characterized by lobular proliferation of ducts with apocrine cellular features surrounded by fibrosclerotic stroma. Although SPA is typically benign, recurrence is not uncommon, and cases with a malignant component have been documented. Thus, complete excision is desirable but preoperative diagnosis is challenging. A 12‐year‐old boy presented with a painless mass in the right neck. We identified a well‐demarcated mass in the right parotid region measuring approximately 2 cm using cervical echography and magnetic resonance (MR) imaging. Fine‐needle aspiration (FNA) revealed two cell types. There were loosely cohesive clusters of polymorphic epithelioid cells with irregular nuclei and abundant vacuolated cytoplasm containing zymogen granules. Some of these cells were binuclear. The other cell types represented normal ductal cells. The original cytological diagnosis was Warthin tumor. Right parotidectomy was performed. Histologically, we observed proliferation of ducts with granular, vacuolated, zymogen granules, and apocrine‐like features in the cytoplasm with hyalinizing sclerotic stroma and some binuclear cells. Four years after parotidectomy, there has been no recurrence or malignant transformation.Cytological diagnosis of SPA is challenging on FNA specimens since SPA is a very rare entity of the salivary gland that can mimic other salivary gland neoplasms. A mixture of apocrine‐like cells and sebaceous‐like cells, nuclear pleomorphism, and zymogen granules can help to diagnose this rare lesion during the initial cytological diagnosis.