Primary small intestine mesenteric low-grade fibromyxoid sarcoma with foci of atypical epithelioid whorls and diffuse DOG1 expression: a case report

Abstract

Background Low-grade fibromyxoid sarcoma (LGFMS) is a rare fibroblastic tumor often involving deep tissue of trunk and lower extremities in young to middle-aged patients. Rarely, LGFMS can occur in other sites including head and neck, chest, abdomen and female reproductive system. Three cases of LGFMS in mesentery of small intestine have been reported and all have conventional histologic features. Herein we reported a unique case of LGFMS in mesentery of small intestine. Case presentation A 43 year-old male with chief complaint of lower back pain for 4 years presented to our hospital. Physical exam reveal a firm, non-tender, non-distended, mobile large abdominal mass, which was shown on abdominal CT as a 10 cm retroperitoneal tumor. Biopsy revealed a spindle cell neoplasm in a myxoid background with a delicate vascular network. Tumor resection was performed. Gross examination of the resected specimen showed a 10.8 cm, tan-white, smooth, firm, lobulated mesenteric mass with bulging and gelatinous cut surface and confined within small bowel serosa. Microscopic examination demonstrated foci epithelioid cords and whorls with prominent atypia, in additional of regular, bland-appearing spindle cells in a fibrous and myxoid stroma and osseous metaplasia. The tumor cells stained diffusely positive for DOG1 with moderate staining density, and diffusely and strongly positive for MUC4. Rearrangement involving FUS (16p11.2) gene was identified with break-apart probe and confirmed by Anchored Multiplex PCR. A final diagnosis of low-grade fibromyxoid sarcoma was rendered. Conclusion Our case highlights the importance of including LGFMS in the differential diagnosis of mesenteric tumors and the DOG1 positivity which could represent a potential diagnostic pitfall.

Novel KMT2B gene mutation in MUC4 positive low-grade fibromyxoid sarcoma

“…LGFM is a rare fibrosarcoma, which is mainly found in the limbs and trunk [ 4 ], but it also occurs occasionally in the scrotum, mediastinum, head and neck [ 5 , 6 , 8 ], while we report that it occurs occasionally in the chest wall and lung. The tumor is mainly composed of alternating collagen like and mucinous areas.…”

Low-grade Fibromyxoid Sarcoma With Heterotopic Bone Formation: Case Report and Review of the Literature

“…Nine additional cases of low-grade fibromyxoid sarcoma with heterotopic ossification for which clinical, radiologic, and pathologic data were available are reported in the literature. 4,6,8,[11][12][13][14][15][16] A summary of these cases is shown in Table 1.…”

“…Due to the lack of information about the clinical, radiologic and pathologic features of these cases, a decision was made not to include them in this review. Nine additional cases of low-grade fibromyxoid sarcoma with heterotopic ossification for which clinical, radiologic, and pathologic data were available are reported in the literature 4,6,8,11–16. A summary of these cases is shown in Table 1.…”

DOG1 expression in neuroendocrine neoplasms: Potential applications and diagnostic pitfalls

“…In routine practice, DOG1 antibody is used as immunohistochemical marker in diagnosis of gastrointestinal stromal tumor (GIST) [13,14], with high sensitivity (ranging between 87% and 94,4% depending on the antibody clone), and high speci city [15][16][17]. In literature, several studies evaluated DOG1 expression in both mesenchimal and epithelial neoplasms other than GIST; indeed, among mesenchimal neoplasms, DOG1 reactivity has been found in low-grade bromyxoid sarcoma, gastrointestinal leiomyoma, myxo brosarcoma, synovial sarcoma, myxoid liposarcoma, undifferentiated pleomorphic sarcoma and in a prostatic stromal sarcoma [18][19][20][21][22]; as concerns epithelial neoplasms, DOG1 expression has been proved in cases of salivary gland, colorectal and endometrial adenocarcinomas, in pancreatic adenocarcinoma and in pancreatic solid pseudopapillary neoplasm, in testicular tumors and in some histotypes of renal cell carcinoma, in poorly differentiated head and neck carcinoma and in a subset of adnexal tumors, with particular correlation with eccrine differentiation neoplasm[16, [23][24][25][26][27][28][29][30]. Furthermore, DOG1 has also been evaluated as a prognostic marker in breast cancer, with con icting results [31,32].…”