Nuchal-type fibroma of the shoulder: A case report and review of the literature.

Nuchal-type fibroma, initially described in 1988 by Enzinger and Weiss, is a rare clinical entity associated with distinct subcutaneous and dermal fibrous tissue proliferation. The etiology of nuchal-type fibroma largely remains to be elucidated. Typical characteristics of this entity include hypocellular, haphazardly arranged collagen with entrapped adipose tissue, paucity of elastin and entrapped small nerves, on which the pathological diagnosis is based. Magnetic resonance imaging (MRI) is the preferred imaging modality for the detection of nuchal-type fibroma, due to its superior soft tissue resolution and multi-planar capabilities. The present study presents the unique findings of a nuchal-type fibroma arising in the shoulder of a 48-year-old man. Distinct features of the nuchal-type fibroma in the present case included hyperintensity on T1- and T2-weighted MRI. Microscopic examination revealed marked mucoid tissue degeneration. To the best of our knowledge, this is the first case report of nuchal-type fibroma presenting with these distinct features. The present findings may therefore assist with the general and differential diagnosis of nuchal-type fibroma.