Low-grade Sinonasal Sarcoma With Neural and Myogenic Features

Abstract

Sarcomas of the sinonasal region are rare. We describe a distinct spindle cell sarcoma of the sinonasal region characterized by concomitant neural and myogenic differentiation. Consultation files and surgical cases from Mayo Clinic were reviewed. Twenty-eight cases were identified that met the inclusion criteria. Clinical data were collected from medical records, consultation letters, and referring pathologists. Reverse transcriptase-polymerase chain reaction for synovial sarcoma fusion transcripts was performed on 18 cases. Cytogenetic studies were performed on 2 cases. The 21 female and 7 male patients ranged in age from 24 to 85 years (mean, 52 y). All cases showed a characteristic histology, which included a cellular spindle cell neoplasm with uniform, elongate nuclei and an infiltrative growth pattern. All tumors demonstrated expression of S-100 with actin positivity in 96% of cases tested. Reverse transcriptase-polymerase chain reaction for synovial sarcoma fusion transcripts was negative in all cases tested. Cytogenetic studies conducted on 2 cases demonstrated the chromosomal translocation t(2;4). The nasal cavity (54%) and ethmoid sinus (57%) were the most commonly involved areas, singly or in combination. Follow-up information was available for 57% (16/28) of cases, with a mean of 8.3 years. Of these, 44% (7/16) experienced at least 1 recurrence. No patient has developed metastases or died of disease. We describe a unique tumor with a characteristic morphologic, immunophenotypic, and cytogenetic profile. On the basis of the locally aggressive nature of this lesion we believe it is best considered a low-grade sarcoma and suggest the term low-grade sinonasal sarcoma with neural and myogenic features.

Recently Described Sinonasal Tract Lesions/Neoplasms: Considerations for the New World Health Organization Book

“…Disease recurred locally from less than 1 year to a maximum of 9 years after treatment. 14 patients were reported to be alive and 2 had died from other causes [13]. There are no reported instances of known regional or distant metastases, and no patients died of disease.…”

“…Local recurrences have been reported in 44 % of cases with follow-up ranging from less than 1-28 years (mean, 8.3 year) [13]. Disease recurred locally from less than 1 year to a maximum of 9 years after treatment.…”

“…t(2;4)(q37.1;q31.3) chromosomal buckled appearing nuclei may be focally identified. Despite the hypercellularity, the tumor cells are highly uniform lacking significant nuclear pleomorphism and increased mitotic activity; d a hemangiopericytomatous vascular pattern may also be present; immunohistochemical staining shows the lesional cells to be reactive for e S100 protein (diffuse and strong) and f muscle specific actin translocation were identified in 2 cases [13]. Distinctive cytogenetic signature has not been reported in any of the neoplasms supporting the notion that LGSSNMF is a separate biological entity likely characterized by a specific fusion gene.…”

“…RT-PCR for SYT-SSX1 and SYT-SSX2 negative in 18 cases evaluated [13]. t(2;4)(q37.1;q31.3) chromosomal buckled appearing nuclei may be focally identified.…”

“…LGSSNMF is also a recently described distinct spindle cell sarcoma of the sinonasal region characterized by concomitant neural and myogenic differentiation [13]. Whether in fact LGSSNMF truly represents a bona fide independent neoplasm rather than a neoplasm that should be subsumed in another defined tumor category (e.g., fibrosarcoma or malignant Schwannoma) [14] remains to be determined requiring the identification and description of additional cases in the literature.…”