Sinonasal tract (SNT)
leiomyosarcoma (LMS) is exceedingly rare with < 100 cases reported. Their relationship to
retinoblastoma and other
malignancies, along with previous irradiation has not been clarified. Routine and consultation cases were reviewed for histologically and immunohistochemically proven SNT LMS. The
tumors were tested with
antibodies against α-smooth muscle actin,
desmin, h-
caldesmon, HMB45,
S100 protein, Rb1, MDM2, CDK4 and EBV (EBER-ISH). Nine
tumors affecting 5 males and 4 females aged 26 to 77 years (median: 48 years) were identified in the maxillary sinus (n = 4), nasal cavity (n = 3) and combined SNT (n = 2). Three patients had previous irradiation (2 for
retinoblastoma, 1 for fibrous dysplasia) and 1 patient had
chemotherapy and
stem cell transplantation for
Hodgkin lymphoma. One patient had prostatic
adenocarcinoma (prior) and rectal
adenocarcinoma (post) to the LMS. All patients with follow-up developed either local recurrences and/or
metastases, principally to lung (time to
metastasis: 16-156 months, mean 62 months). Histologically, 6
tumors were conventional high-grade LMS, two had
glycogen-rich clear cell (
PEComa-like) morphology and one was spindle cell low-grade. The latter showed grade 2 in the recurrence and grade 3 in the lung
metastases. Two cases showed dedifferentiation to anaplastic pleomorphic (inflammatory MFH-like) phenotype. Immunohistochemistry revealed diffuse expression of at least 2 smooth muscle markers in 8 and only actin in one case/s. All other markers were negative. RB1 loss was observed in 6/8 cases tested. Sinonasal tract
leiomyosarcomas are rare aggressive
sarcomas that frequently develop in a background of previous
cancer therapy (4/9), most frequently irradiation. Their varied morphology underlines the wide differential diagnostic considerations. Long-term survival may be achieved with aggressive multimodal
therapy.