Multifocal Malignant Proliferating Trichilemmal Tumor: A Diagnostic Imitator Beyond the Scalp
January 2026
in “
International Journal of Research and Innovation in Applied Science
”
Studysummary This case report details a rare instance of malignant proliferating trichilemmal tumour in a 60-year-old male, emphasizing the significance of histochemical and immunohistochemical markers for accurate diagnosis and differentiation from squamous cell carcinoma.
Our plain-language summary. Not medical advice or a treatment recommendation. Consult a qualified healthcare professional before changing treatment. Full disclaimer
Malignant proliferating trichilemmal tumour (MPTT) is a rare skin cancer originating from the hair follicle's outer root sheath, accounting for less than 0.1% of skin malignancies. It typically appears as a single scalp lesion in elderly women, but this case involved a 60-year-old male with painful swellings on the scalp and left scapular region. Histopathological analysis showed significant cytological atypia and trichilemmal keratinization, with immunohistochemistry revealing CD34 expression, strong nuclear p53, and a high Ki-67 index, confirming MPTT. Multifocal MPTT in males is extremely rare, and recognizing trichilemmal keratinization along with specific markers is crucial for differentiating MPTT from squamous cell carcinoma and ensuring proper treatment.
