Minimal deviation spindle cell melanoma: unusual histologic pattern in an 11-year-old black girl

An 11-year-old black girl presented with a nodule at the tip of the left thumb that eroded the underlying tip of the distal phalanx. The tumor was composed of junctional nests and uniform atypical spindle melanocytes that formed broad fascicles and diffusely permeated the dermis. Scattered collections of Kamino bodies were present. A single enlarged left axillary lymph node was noted 9 months after the initial presentation. The lymph node measured 7 x 4.5 x 2.5. cm and was replaced by metastatic tumor composed of fascicles of spindle melanocytes. Immunohistochemical examination demonstrated immunoreactivity for S100, HMB45, and Leu 7, and ultrastructural examination revealed the presence of premelanosomes in the primary and metastatic tumor. Now, more than 10 years since her initial presentation, the patient is well with no further manifestation of the disease.