Desmoplastic Melanoma



Desmoplastic Melanoma


Soheil Sam Dadras, MD, PhD

Olubukola Babalola

David Cassarino, MD, PhD










DM may resemble an inflamed scar on low-power examination. However, aggregates of lymphoid cells image and prominent solar elastosis image are usually identified and are helpful findings.






High-magnification examination shows hyperchromatic-staining atypical spindle cells image surrounded by abundant collagen image bundles.


TERMINOLOGY


Abbreviations



  • Desmoplastic melanoma (DM)


Synonyms



  • Desmoplastic/neurotropic melanoma


Definitions



  • Form of invasive melanoma composed of spindle cells associated with dense stromal collagen, resembling a scar


CLINICAL ISSUES


Epidemiology



  • Age



    • Presents in sun-damaged skin of elderly adults


Presentation



  • Firm skin-colored, tan or pink plaque or nodule


  • Sometimes depressed


  • Often amelanotic


Treatment



  • Surgical approaches



    • It is important to resect DM with clear surgical margins as early as possible for successful clinical management


    • There is increasing evidence that sentinel lymph node biopsy may not be indicated for “pure” variants of DM because of the low incidence of regional lymph node metastases


Prognosis



  • Tumor thickness


  • Clark level (IV vs. V)


  • Histological subtype: “Pure” (longer disease-free survival) vs. “combined”



    • “Pure” subtype is defined as > 90% scar-like areas


    • “Combined” subtype is defined as densely cellular spindle cell collections without significant scar-like areas (> 10%)


  • Tumor mitotic rate


MICROSCOPIC PATHOLOGY


Histologic Features



  • Ill-defined spindle cell neoplasm with highly infiltrative pattern of growth


  • Overlying epidermis may show melanoma in situ (usually lentigo maligna type)


  • Stromal collagen on scanning magnification resembles a scar


  • Spindle cells are arranged in fascicles and merge with scar-like areas


  • Cellular density and cytologic atypia can vary based on histologic subtype


  • Discrete dermal lymphoid aggregates


  • Solar elastosis

Jul 8, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Desmoplastic Melanoma
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