Pilomatrixoma and Pilomatrical Carcinoma

Pilomatrixoma and Pilomatrical Carcinoma

Senait W. Dyson, MD

David Cassarino, MD, PhD

Low magnification of a pilomatrixoma shows a nodularcystic dermal-based lesion with a thin, partial rim of peripheral basaloid cells image surrounding central collections of eosinophilic and shadow cells image.

Higher magnification shows the 2 cell types of PMX: Basaloid image and shadow cells image. In this case, transitional cells image with pyknotic nuclei (prior to becoming shadow cells) are also seen.



  • Pilomatrixoma (PMX)


  • Pilomatrixoma

    • Pilomatricoma

    • Calcifying epithelioma of Malherbe

    • Trichomatricoma

  • Pilomatrical carcinoma

    • Matrical carcinoma

    • Malignant pilomatrixoma

    • Pilomatrix carcinoma


  • Pilomatrixoma

    • Benign dermal &/or subcutaneous tumor

    • Derived from matrical portion of hair follicle

  • Pilomatrical carcinoma

    • Malignant counterpart of pilomatrixoma



  • Derived from matrix of hair follicle

  • Mutation in the CTNNB1 gene seen in both pilomatrixoma and pilomatrical carcinomas

    • CTNNB1 gene encodes β-catenin


  • Rare cases are associated with myotonic dystrophy and Rubinstein-Taybi syndrome

    • Usually multiple pilomatrixomas present

  • Cysts of Gardner syndrome can show pilomatricoma-like changes



  • Incidence

    • Pilomatrixoma

      • Relatively common

    • Pilomatrical carcinoma

      • Very rare

  • Age

    • Pilomatrixoma

      • Young children (1st and 2nd decade)

      • Rare in adults

    • Pilomatrical carcinoma

      • Elderly

  • Gender

    • Pilomatrixoma

      • No gender predilection

    • Pilomatrical carcinoma

      • Male predominance (M:F = 5:1)


  • Pilomatrixoma and pilomatrical carcinoma

    • Head and neck and upper limbs

Jul 8, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Pilomatrixoma and Pilomatrical Carcinoma

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