Typical and Atypical Granular Cell Tumors of Soft Tissue: A Clinicopathologic Study of 50 Patients.

Abstract

Granular cell tumors are rare neoplasms of neural origin. Despite the mesenchymal nature of these tumors, they rarely occur in the soft tissue, and as a result, this subset is not well characterized. We present the largest case series to date comprising 50 patients with benign and atypical soft tissue granular cell tumors in an effort to better define the pathologic features in this subset of lesions. All cases of soft tissue granular cell tumors from the Ohio State Medical Center and the Medical College of Wisconsin over a 10-year period were reviewed for histologic and clinical findings. The most common location was the upper extremity. The mean age was 38.6 years, and the mean size of the tumor was 2.1 cm. An infiltrative growth pattern was seen in 58.8% of cases, and positive margins were found in 68.2%. Eleven (21.6%) cases showed evidence of cytologic atypia and fulfilled the criteria for a diagnosis of atypical giant cell tumor. Two of 11 patients with long-term follow-up experienced local recurrence. Compared with granular cell tumors overall, the soft tissue subset shows a larger average size and higher propensity for incomplete resections, with atypical features being relatively common. Our findings suggest that soft tissue granular cell tumors may be slightly more aggressive than their dermal or organ-confined counterparts.