Background: Fine needle aspiration cytology (FNAC) can be used for establishing a diagnosis of cutaneous lesions, especially in cases with cyst formation. Poroid hidradenoma is eccrine neoplasm with both solid and cystic components.
Case: A 77-year-old female presented with a slightly elevated nodule in the skin on her left elbow. The tumor was well demarcated, 2.7 x 2.4 cm and soft, and overlying skin was slightly reddish. FNAC revealed two types of cell: one had abundant cytoplasm in which small to large, occasionally multinucleated nuclei with small but distinct nucleoli were evident. Chromatin was finely granular, and nuclear membrane was thin and almost smooth. Another type of cell had scanty cytoplasm and a round to oval nucleus with small but prominent nucleoli. Histologic diagnosis was poroid hidradenoma.
Conclusion: FNAC can be useful for diagnosing intradermal cystic lesions before surgical resection.