2487. Fibroadipose Proliferation in the Posterior Neck Subcutaneous Tissue Simulating Neoplasm
Authors * Denotes Presenting Author
  1. Mark Murphey *; Uniformed Services University
  2. Jennifer Ficke; Walter Reed National Military Medical Center
  3. Stephen Savioli; Walter Reed National Military Medical Center
  4. Alexander Galifianakis; Walter Reed National Military Medical Center
  5. Alejandro Luina Contreras; Joint Pathology Center
  6. Christian Curcio; Joint Pathology Center
  7. James Jelinek; Washington Hospital Center
To describe fibroadipose proliferation typically localized in the posterior, inferior neck subcutaneous tissues that can simulate a neoplastic process, radiologically and clinically.

Materials and Methods:
We retrospectively review available demographics, imaging and pathologic material from 16 recent cases of lesions that presented clinically as soft tissue masses in the posterior and inferior subcutaneous tissues of the neck. Pathologic material from either biopsy or resection (n = 13) was reviewed for evidence of neoplasm versus a more reactive process. Radiologic studies reviewed included ultrasonography (US; n = 5), CT (n = 2) and MR imaging (n = 14). Imaging was evaluated for evidence of soft tissue mass and intrinsic characteristics by three musculoskeletal radiologists with agreement by consensus.

All patients studies were men with an age range of 20-30 years (average, 25 years). All patients were clinically diagnosed as showing features suspicious for a soft tissue neoplasm owing to discomfort and fullness in the subcutaneous tissues of the posterior inferior neck. Imaging features were reported as demonstrating a mass leading to subsequent biopsy or surgical resection (n = 13). On a retrospective review sonography, CT and MRI revealed no evidence of a discrete soft tissue mass but distortion and replacement of the subcutaneous fat architecture with associated edema on water-sensitive MRI sequences. Histologic evaluation showed fibroadipose proliferation with expanded nuchal-type collagen and mature adipose tissue and no evidence of a neoplastic process. All patients were involved with weightlifting.

We report 15 cases of pathologically proven (n = 14) fibroadipose proliferation involving the posterior and inferior subcutaneous tissues of the neck simulating a neoplastic process on clinical and/or radiologic evaluation. We postulate that these lesions represent reactive changes in the subcutaneous fat, likely related to repetitive weightlifting actively with barbell positioning. Recognition of this entity is important to obviate the need for biopsy or surgical resection.