Granular Cell Tumor

Granular cell tumors were described as early as 1926 by the Russian pathologist Abrikossoff. They were initially coined granular cell myoblastomas, as they were believed to be of muscular origin. With the advent of immunohistochemical stains and electron microscopy, they are now believed to be Schwannian derivation. Notably, a subset of S100-negative “non-neural” granular cell tumors have been identified which may not derive from neural tissue.These rare tumors are most commonly reported in the skin, oral cavity, digestive tract, and subcutaneous tissue. However, they can occur anywhere in the body, including breast, bladder, nervous system, respiratory and genitourinary tracts. All age groups and genders can be affected, but it is classically found in women in their 4th to 6th decades of life. Granular cell tumors typically present as solitary, painless nodules less than 3-4 cm large and may be found incidentally.The vast majority behave indolently. Based on histologic criteria or the presence of metastasis, however, 1% to 2% of these lesions can be malignant, with poor prognosis and few curative options beyond surgical excision.