Granular cell tumor of hand presenting as subcutaneous nodule mimicking dermal adnexal tumor: A diagnosis by cytology

Granular cell tumor (GCT) is an uncommon tumor and is believed to be of schwannian origin. GCT is benign but rare malignant cases are recorded. GCT occurs in almost any part of the body. The common sites are the tongue, skin, and subcutaneous tissue. GCT of hand is an extremely rare. Till date only 17 cases are reported in the literature. Preoperative diagnosis of GCT is important, because GCT mimics dermal adnexal tumor in subcutaneous tissue, other soft tissue tumor or inflammatory lesions. GCT is composed of large polygonal cells with eosinophilic granular cytoplasm and these cells are often immunoreactive for the S-100 protein. Fine-needle aspiration cytology has been suggested to be diagnostic modality of choice and this would undoubtedly aid the correct diagnosis. Excision with wide surgical margins is curative for benign GCT. Recurrence and malignant transformation requires regular follow-up. Here, this communication documents a case of cytological diagnosis of the granular cell tumor of hand in a 21-year-old female, clinically suspected to be a dermal adnexal tumor.