Myxoinflammatory Fibroblastic Sarcoma: Morphologic and Genetic Updates

Abstract

Myxoinflammatory fibroblastic sarcoma (MIFS) is a malignant mesenchymal neoplasm most frequently arising in the distal extremities of adults, which usually behaves in a low-grade manner but is capable of metastasizing to local and distant sites, rarely leading to death. It is a rare tumor whose unusual morphology can lead to erroneous histologic diagnosis, either as a nonneoplastic (infectious or inflammatory) process or as a variety of neoplastic diseases. While its exact origin is uncertain, ultrastructural studies have shown at least some of the constituent cells to be modified fibroblasts. Distinct and reproducible genetic abnormalities identified in MIFS are translocation t(1;10)(p22:q24), with rearrangements of the TGFBR3 and MGEA5 genes associated with increased levels of FGF8, and formation of marker/ring chromosome 3, with amplification of the VGLL3 locus. Because these genetic abnormalities are shared by both MIFS and hemosiderotic fibrohistiocytic lipomatous tumor, it is thought that these 2 morphologically distinct neoplasms may comprise a spectrum of disease defined by these genetics. We review the literature on MIFS and discuss morphology (including that of MIFS/hemosiderotic fibrohistiocytic lipomatous tumor hybrid lesions), immunohistochemistry, the differential diagnosis, and recent molecular genetic developments.

Myxoinflammatory fibroblastic sarcoma: A rare case affecting only the dermis

“…MIFS is a multinodular neoplasm usually situated in the subcutis, whence it may extend to deeper soft tissues and to the dermis; it is therefore of dermatopathological interest . In the case reported here, the neoplasm solely affected the dermis, prompting the need for differential diagnosis in order to rule out other myxoid cutaneous tumors.…”

Acral manifestations of soft tissue tumors

“…Radiotherapy has supplemented wide local excision in some cases, but data are limited on its utility. 61 Gross examination discloses a multinodular lesion measuring several centimeters and having a variably myxoid to fibrous cut surface. Microscopic findings parallel the gross findings, indicating a multinodular lesion with alternating zones of fibrous and myxoid regions ( Figure 17 A and B).…”

“…19,61 "Inflammatory myxohyaline tumor" was a previous designation for this entity, 62 but the current name better captures the biologic potential and apparent morphogenesis. Myxoinflammatory fibroblastic sarcoma (MIFS) is a low-grade sarcoma with a fibroblastic phenotype that most often develops on the distal extremities of adults.…”

“…Cases of overlapping MIFS/FHLT have been described. 61,63 The underlying pathobiology of MIFS and FHLT has yet to be elucidated.…”

Myxoinflammatory Fibroblastic Sarcoma of the Scalp

“…1 MIFS is described as a low-grade sarcoma with a high rate of local recurrence (up to 67% in one series) 2 but a very low rate of metastasis. Only 4 cases of regional lymph node metastasis have been described (3 cases of inguinal metastases and 1 case at an unspecified site) and 2 cases with subsequent lung metastases.…”