A 35-year-old man with a history of HIV presented with difficulty breathing. Bronchoscopy reviewed a submucosal mass and a biopsy was performed.
Microscopically the mass consisted of fusiform spindled cells with relatively uniform nuclei, and prominent eosinophilic cytoplasm. Mitotic figures were present but rare and there was no evidence of tumor necrosis.
What is your diagnosis?
As seen above the neoplastic cells were strongly positive for smooth muscle actin.
In-situ hybridization for Epstein-Barr virus encoded RNA (EBER) was strongly positive as seen above.
This is an example of an EBV-associated smooth muscle tumor (EBV-SMT). The number of reported EBV-SMT's arising in severely immunosuppressed patients (usually with AIDS) has steadily increasing since the first description in the mid-1990s. A 2011 review by Purgina et al (Pathology Research International 2011) identified 53 articles in the English language literature, including 64 reported cases of EBV-SMT. The majority of these reports involved patients who were young, severely immunosuppressed, and had multifocal tumors. The central nervous system was the most common site to be involved, but the tumors are noted to arise in very unusual sites for smooth muscle neoplasms, including the vocal cords and orbit, and they are frequently multicentric.
Histologically, tumors had smooth muscle features and were immunoreactive for muscle markers and almost invariably demonstrated the presence of EBV by in situ hybridization or PCR. Importantly, while mitotic figures and necrosis are used to separate leiomyoma from leiomyosarcoma, when applied to smooth muscle tumors NOT associated with EBV, these features do not correlate with clinical outcome in the patients with EBV-SMT's.
Treatment consists primarily of resection, and less often radiotherapy, chemotherapy and highly active antiretroviral therapy. Overall, EBV-SMTs appear to have variable aggressiveness and clinical outcome and may exhibit a more favorable prognosis compared to conventional leiomyosarcoma. Tumor-related deaths from EBV-SMT occurred in only 4 of 51 patients.
The list of EBV-associated neoplasms continues to grow!
This wasn't one of my personal consult cases. I "borrowed" it from somewhere and placed the photographs in my teaching image file. For the life of me, I can't remember where I got it, so I apologize for not giving appropriate credit!