Giant hypopharyngeal atypical lipomatous tumor.

The so-called "giant fibrovascular polyps" of the esophagus and hypopharynx typically present as sausage-like pedunculated structures that protrude into the lumen and cause obstructive symptoms. Most are cured by local resection but they may recur. Microscopically, they display an admixture of fibrovascular and adipose tissue that is coated by unremarkable squamous mucosa. Here, we report a case that had scattered hyperchromatic cells and lipoblasts within the adipose tissue component. In other anatomic sites similar appearing lesions have been interpreted as pedunculated liposarcomas/atypical lipomatous tumors that are more prone to local recurrences than classic giant fibrovascular polyps. Reports of dedifferentiation and metastases are lacking thus raising the possibility that the cytologic findings in such lesions are degenerative. To confirm our suspicion of liposarcomatous differentiation, we performed immunohistochemistry for MDM2 and p53, 2 markers that are known to be negative in benign lipomatous lesions and positive in well-differentiated liposarcomas/atypical lipomatous tumors. The scattered atypical hyperchromatic cells and the lipoblasts both exhibited strong nuclear staining for both markers and supported the diagnosis of pedunculated giant hypopharyngeal atypical lipomatous tumor.