Fibromyxoid sarcoma of maxilla

A recurrent mass in the nose can pose diagnostic and therapeutic challenges. Even more so, if it exhibits rapid growth, displays unusual clinical features, is a rare histopathological diagnosis or if the patient is unavailable for regular follow-up. We present a case of a middle-aged retrovirus-positive man who underwent surgical removal of a recurrent nasal mass. Histopathology revealed a diagnosis of low-grade fibromyxoid sarcoma, a rare entity in the sinonasal tract. Immunohistochemistry plays a crucial role in clinching the diagnosis, especially for lesions with fibrous and myxoid components. Early and complete surgical resection diminishes the likelihood of recurrence and metastasis.

Low-grade fibromyxoid sarcoma with heterotopic bone formation: case report and review of the literature

Introduction/Objective Low-grade fibromyxoid sarcoma (LGFMS) is an uncommon soft tissue malignancy with deceptively bland histologic appearance, and a tendency for late recurrence and metastasis. Cases with significant heterotopic ossification are rare. This presentation aims to characterize the features of LGFMSs showing heterotopic ossification reported in the literature, and further review the morphologic spectrum of this malignant neoplasm. Methods/Case Report We report the case of a 42-year-old male presenting with a 20-year history of a painless tumor in his left upper thigh. Computed tomography images showed coarse punctate peripheral calcifications, and the mass was resected. The tumor cells were immunohistochemically positive for MUC4, and positive for FUS (16p11.2) gene rearrangement by fluorescence in situ hybridization. Lamellar and woven bone with admixed adipose tissue was seen. Immunohistochemistry also showed focal weak to moderate staining for TLE-1. An English literature search using the terms “Evans tumor”, “low-grade fibromyxoid sarcoma”, “ossification”, “osseous metaplasia”, “bone metaplasia” and “bone formation” was performed. Nine cases were identified. The majority of subjects were males, with a mean age of 38 years (range of 12-61 years). The duration of symptoms before diagnosis ranged from a few months to 10 years. The tumor size ranged from 2.5 and to more than 12 cm. In a minority of subjects, calcifications were identified on imaging studies. Histologically, bone metaplasia was mainly seen at the periphery of the tumor. The majority of cases had a chromosomal translocation (FUS-CREB3L2 in 5 cases and EWSR1-CREB3L1 in one). Results (if a Case Study enter NA) NA Conclusion LGFMS is a tumor that can occur in a wide range of anatomical sites, and should be included in the differential diagnosis of any spindle cell neoplasm with hypocellular areas and bland cytology. Pathologists and clinicians should be aware of the rare possibility of heterotopic ossification in this tumor type, which can be radiologically detected as calcification and then confirmed histopathologically.

Soft tissue perineurioma involving the kidney: a report of two cases with an emphasis on differential diagnosis

Background Soft tissue perineurioma of the kidney is rare, with only a few reported cases. We report two additional cases with histologic, immunohistochemical and genetic analyses. Case presentation Both tumors were from adults (1 female aged 49 years and 1 male aged 42 years) and grossly had maximum diameters of 6.5 and 10 cm, respectively. The tumors were overall well circumscribed but unencapsulated, with focally entrapped benign native renal tubules in one case; both tumors seemed to arise in the capsular areas. The tumors had histologic and immunohistochemical profiles consistent with soft tissue perineurioma. Fluorescence in situ hybridization analyses demonstrated that the tumors were negative for amplification of MDM2 and rearrangements of ESWR1, FUS, and KMT2A. Targeted next-generation sequencing revealed a low tumor mutation burden and likely pathogenic mutations (CYP2B6 and FLT1 mutations for 1 each). Follow-up data were available for both patients; neither had tumor recurrence or metastasis. Conclusions In conclusion, renal perineurioma is rare, usually arises in the capsular areas, and is cured by resection. Low-grade dedifferentiated liposarcoma and low-grade fibromyxoid sarcoma as well as other spindle cell lesions should be considered in the differential diagnosis.