Desmoplastic malignant melanoma: rare and difficult to diagnose.

Abstract

We review our experience with a recent cluster of three cases of rare desmoplastic malignant melanoma (DMM). Our purpose is to alert clinicians to this rare tumor and the difficulty in clinical and histopathologic diagnosis. The clinical presentation and steps necessary to establish diagnosis are outlined. A literature review on diagnosis, treatment, and prognosis is presented. Two thirds of DMM are amelanotic and may appear only as a dermal nodule or thickening. Diagnosis can be made with the combination of light microscopy and immunopathology. Treatment consists of surgical excision. Lymph node dissection should be considered only when histologically positive regional nodes are present. The diagnosis of DMM may be difficult when based only on clinical expectation of melanoma and light microscopy findings. A strong clinical suspicion of DMM coupled with immunologic studies will establish the diagnosis.