Trichilemmal cyst

Case contributed by Dr Antonio Rodrigues de Aguiar Neto


Arterial hypertension and headache.

Patient Data

Age: 80 years
Gender: Female

Non contrast CT Brain


There are several well-circumscribed nodules affecting the skull's subcutaneous tissue layer of the scalp, with punctate and coarse calcifications located within the lesions. The subcutaneous fat around the lesion is intact without stranding or edema. All nodules appeared as round or ovoid mass lesions underneath an intact cutis, and there is the preservation of the underlying outer table of the skull vault. The largest one is located in the frontal region, measuring 1.2 x 1.3 cm.  

Impression: The CT features are consistent with multiple trichilemmal cysts.

Case Discussion

Trichilemmal cysts, also known as pilar cysts, are a solid-cystic lesion arising from the hair follicle 1-7. They are the most common cutaneous nodule in the scalp, with a preference for middle-age women 1-3,5-7. Trichilemmal cysts are usually benign, but they may present in a low potential neoplastic form, which results in proliferating trichilemmal cysts 1-7.

This patient presents asymptomatic noninfiltrating scalp lesions containing calcifications confined within the head's skin and subcutaneous fat. Although the definitive diagnosis is histological, these CT findings favor the diagnosis of trichilemmal cysts.

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