#dermpathJC April 2020 summary

#dermpathJC April 2020:

Thursday, April 30th, 9 pm EST

Article discussed: Cutaneous carcinosarcoma: a series of six cases and a review of the literature

Authors: Joshua J. Clark, Anneli R. Bowen, Glen M. Bowen, John R. Hyngstrom, Michael L. Hadley, Keith Duffy, Scott R. Florell and David A. Wada

Open access courtesy of Journal of Cutaneous Pathology: https://onlinelibrary.wiley.com/doi/epdf/10.1111/cup.12843

Summary prepared by: Cacey Peters, M.D. (@caceypeters)


Journal Club Summary:

  • Coined by Virchow in 1864, the term carcinosarcoma refers to a biphasic malignant neoplasm with epithelial and mesenchymal components which can be seen in virtually every organ
  • In primary cutaneous carcinosarcoma, the most common epithelial components are basal cell and squamous cell carcinomas, whereas the less common include malignant spiradenoma, porocarcinoma, pilomatrical carcinoma, and trichoblastic carcinoma
  • The mesenchymal component includes fibrosarcoma, pleomorphic undifferentiated sarcoma (previously called malignant fibrous histiocytoma), osteosarcoma, chondrosarcoma, and rhabdomyosarcoma
  • Although cutaneous carcinosarcomas are rare, they are likely under-reported due to lack of awareness, tissue sampling variation, and the variety of clinical/histological phenotypes
  • Of the reported cases reviewed, most occurred on sun-exposed areas of the head and extremities with age ranges from 32 to 98 years old, most cases occurring in the 8th and 9th decades of life
  • Male predominance was found to be 1.7:1
  • Recurrence and death were more common from adnexal carcinosarcomas with equal distribution among the various adnexal groups
  • Patients with basal cell carcinosarcoma had longer disease-free survival than those with squamous cell carcinosarcoma
  • The two hypotheses of the origin of carcinosarcoma include a monoclonal carcinoma that undergoes metaplasia with loss of residual epithelial differentiation versus a convergence of two or more distinct progenitor cells
  • Multiple molecular studies of non-cutaneous carcinosarcomas favor a monoclonal cell population with differentiation into both epithelial and mesenchymal components
  • Basal cell carcinosarcoma has been shown to be related to sun damage with mutations in PTCH1, p53, p63, and p13 genes
  • Squamous cell carcinosarcoma has been shown to have point mutations and deletions in the TP53 gene
  • The main histologic differential diagnosis of malignant biphasic neoplasms includes sarcomatoid carcinoma, malignant mixed tumor, biphasic synovial sarcoma, and malignant peripheral nerve sheath tumor
    • Sarcomatoid carcinoma (spindle-cell squamous carcinoma) = malignant spindle cells with some degree of typical squamous cell carcinoma which can be proven with immunohistochemistry (IHC) for keratins and/or p63 by the spindle cells
    • Biphasic synovial sarcoma = uncertain histogenesis; extremities; young adults; epithelial cells in cords/nests/glands with admixed cellular, monotonous spindle cell proliferation; confirmed with TLE1, EMA, and/or cytokeratin as well as t(X;18) translocation
    • Malignant mixed tumors of the skin = contain carcinoma admixed with benign myxoid or chondroid proliferations; may be S100+
    • Malignant peripheral nerve sheath tumor (MPNST) = rarely can have mucin-producing glands with cuboidal/columnar cells admixed with malignant spindle cells that otherwise fits criteria for the typical MPNST
  • Three diagnostic criteria have been proposed for primary cutaneous carcinosarcoma
    • Clearly defined dual neoplasm with explicit characterization via histology and IHCs
    • Exclusion of metastasis from other sites
    • Exclusion of sarcomatous stromal changes around otherwise normal stroma of a carcinoma
  • There is a lack of criteria to differentiate squamous cell carcinoma with sarcomatoid differentiation from cutaneous carcinosarcoma
  • Management of cutaneous carcinosarcoma depends on the clinical and histologic features
    • The epithelial component correlates with metastasis
      • Basal cell carcinosarcoma = low-risk (2%)
      • Squamous carcinosarcoma and adnexal carcinosarcoma = (12-50%)
    • Tumor size, recent growth, metastases, and tumor chronicity may also affect management but are limited in number for definitive recommendations

Memorable Tweets:

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Until next month #dermpathJC, stay safe!

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