Case contributed by Dr Kamel Mahmoud Alkhateeb


Painless swelling over the left side of the neck gradually increasing in size over 1 month.

Patient Data

Age: 30 years
Gender: Male

A well-defined ovoid heterogeneous mass measuring ~27 x 15 mm is seen on the left side of the neck within subcutaneous tissues. It is mainly echogenic with multiple hypoechoic internal septae. Low level of peripheral vascularity is present. No associated lymphadenopathy is seen on the left side.


There is subcutaneous well-defined oval focal mass lesion seen in the left side of the neck, superficial to left sternomastoid muscle, measuring ~ 24 x 22 x 16 mm causing impression upon the muscle with obliteration of the fat plane. Tiny calcifications could be seen inside. Subcutaneous mild stranded fat is seen surrounding the lesion. The lesion shows heterogeneous enhancement on post-contrast images.

Excision biopsy

Section reveals skin with a lesion in the dermis comprised of a basaloid proliferation resembling the hair matrix cells, maturing into structureless eosinophilic cells lacking nuclei called shadow cells. Mixed inflammatory infiltrates with neutrophils, lymphocytes and plasma cells seen. Histiocytic infiltrate with multinucleated cells forms at sites of rupture noted. Focal melanophages are seen.No overt atypia seen. Resection margins are clear of the lesion.

Consistent with Pilomatrixoma. No evidence of malignancy seen.

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Case information

rID: 66503
Published: 23rd Feb 2019
Last edited: 28th Nov 2019
Inclusion in quiz mode: Included

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