Lymph node biopsy results for desmoplastic malignant melanoma

Desmoplastic malignant melanoma (DMM) is a rare variant of melanoma with distinct histopathologic and clinical features. Compared with other melanomas, the desmoplastic variant demonstrates a greater frequency of local recurrence and a proclivity for tracking along nerves, but it poses a lower risk of distant metastases. Elective lymph node dissection and sentinel lymph node biopsy (SLNB) are commonly used tools for determining prognosis in thick melanomas. The role of these procedures for DMM remains unclear. This study was designed to characterize DMM and determine the frequency of histologically positive lymph nodes in patients with DMM. This retrospective chart review included patients with DMM treated by Johns Hopkins Hospital (JHH) physicians between 1998 and 2003. Among the 28 patients included in the study, 18 patients had biopsies performed on lymph nodes (15 SLNBs and 3 radical neck dissections). One patient had a sentinel lymph node with histology positive for DMM. All others had negative results from histology and S100 stains. This study suggests that the frequency of positive SLNBs in DMM may be substantially lower than that of other melanomas.