Myxoinflammatory fibroblastic sarcoma of the scalp: aggressive behavior at a rare, nonextremity site

Myxoinflammatory fibroblastic sarcoma of the liver: Case report and literature review

RATIONALE

Myxoinflammatory fibroblastic sarcoma (MIFS) is a rare low-grade malignant soft tissue sarcoma that primarily affects the distal extremities in adults, with the highest incidence in patients in their 40s and 50s. It has a high local recurrence rate and a low metastasis rate. Although MIFSs have been documented in other sites, an MIFS in the liver is highly unusual. Herein, we present a case of a patient with hepatic MIFS.

PATIENT CONCERNS

The patient was a 58-year-old Chinese man with abdominal pain as the primary symptom. Abdominal computed tomography and magnetic resonance imaging revealed a mass in the right posterior lobe of the liver. The patient underwent surgical excision, and the excised specimen was identified as MIFS. Three years later, the patient returned to our hospital for abdominal pain. Computed tomography and magnetic resonance imaging revealed a mass in liver segments 2/3/4.

DIAGNOSIS

Postoperative pathological examination of the tumor revealed the recurrence of MIFS.

INTERVENTIONS

The patient underwent surgical resection of the MIFS.

OUTCOMES

The patient received multiple pirarubicin-based chemotherapy treatments and an ALK inhibitor (anlotinib) within 6 months after surgery, but the tumor recurred.

LESSONS

MIFS can not only occur in the proximal limbs, trunk, head, and neck but can also affect the abdominal organs. Surgical resection remains the primary treatment option for MIFS in the absence of any contraindications. Because the recurrence rate of MIFS is high, meticulous long-term monitoring is required.

Myxoinflammatory fibroblastic sarcoma: an immunohistochemical and molecular genetic study of 73 cases

Myxoinflammatory fibroblastic sarcoma (MIFS) is a rare, low-grade soft tissue neoplasm preferentially arising in the extremities of young to middle-aged adults characterized histologically by a variegated appearance and absence of a distinctive immunophenotype. Herein we have evaluated a series of 73 cases of MIFS to define potential features and markers that may facilitate diagnosis. An immunohistochemical study with a large panel of antibodies showed strong positivity of the tumor cells for bcl-1 (94.5%), FXIIIa (89%), CD10 (80%), and D2-40 (56%). FISH and array comparative genomic hybridization (aCGH) were performed in a large subset of cases to investigate the utility for detecting the TGFBR3 and OGA t(1;10) rearrangement and BRAF abnormalities. Using a combination of FISH and/or aCGH, t(1;10) was detected in only 3 of 54 cases (5.5%). The aCGH study also demonstrated amplification of VGLL3 on chromosome 3 that was detected in 8 of 20 cases (40%). BRAF alterations were observed by FISH in 4 of 70 cases (5.7%) and correlated with gain of chromosome 3p12 (VGLL3). A novel fusion transcript involving exon 6 of ZNF335 and exon 10 of BRAF was identified in one case. Demonstration of amplification of VGLL3 on chromosome 3 in combination with expression of bcl-1 and FXIIIa may help support the diagnosis, however, due to their low specificity these markers are not sufficient for a definitive diagnosis in the absence of the appropriate clinical-pathological context. Until a more robust genetic or immunohistochemical signature is identified, the diagnosis of MIFS rests on its characteristic clinicopathological features.

Acral myxoinflammatory fibroblastic sarcoma with hybrid features of hemosiderotic fibrolipomatous tumor occurring 10 years after renal transplantation

Myxoinflammatory fibroblastic sarcoma is a rare malignant soft tissue neoplasm that typically arises on the distal extremities of adults. It usually behaves in a low-grade manner and its characteristic histology is of a lobulated proliferation of moderately atypical spindled to epithelioid cells, vacuolated cells, and enlarged or bizarre cells with prominent nucleoli, dispersed within myxoid stroma containing a mixed inflammatory cell infiltrate. The etiology of myxoinflammatory fibroblastic sarcoma remains unknown with no definite causal factors identified. We describe a case of myxoinflammatory fibroblastic sarcoma arising in the foot of a 77-year-old female, which rapidly recurred locally after initial excision and which arose 10 years after renal transplantation. The neoplasm also showed intermingled areas of hemosiderotic fibrolipomatous tumor. The patient also had multifocal areas of squamous cell carcinoma in situ of the foot and hand, in keeping with the clinical context of immune deficiency. This is the second case of myxoinflammatory fibroblastic sarcoma reported to occur after transplantation, but additionally shows hybrid features of hemosiderotic fibrolipomatous tumor, highlights immunocompromise/immunosuppressive therapy as a possible etiologic factor in their development, and adds to the growing number of myxoinflammatory fibroblastic sarcoma that has demonstrated aggressive behavior.

Recurrent BRAF Gene Rearrangements in Myxoinflammatory Fibroblastic Sarcomas, but Not Hemosiderotic Fibrolipomatous Tumors

Myxoinflammatory fibroblastic sarcoma (MIFS) is a low grade soft tissue sarcoma with a predilection for acral sites, being associated with a high rate of local recurrence but very infrequent distant metastases. Although a t(1;10) translocation resulting in TGFBR3-MGEA5 fusion has been reported as a recurrent genetic event in MIFS, this abnormality is seen only in a subset of cases. As no studies to date have investigated the spectrum of alternative genetic alterations in TGFBR3-MGEA5 fusion negative MIFS, we undertook a genetic analysis of this particular cohort for further molecular classification. Triggered by an index case occurring in the finger of a 37-year-old female and harboring a novel TOM1L2-BRAF fusion by targeted RNA sequencing we investigated potential recurrent BRAF abnormalities by screening a large group of 19 TGFBR3-MGEA5 fusion negative MIFS by fluorescence in situ hybridization. There were 6 (32%) additional MIFS with BRAF genetic abnormalities, including 5 gene rearrangements and one showing BRAF amplification. Interestingly, VGLL3 amplification, a recurrent genetic abnormality coexisting with t(1;10) in some MIFS, was also detected by fluorescence in situ hybridization in 4/6 (67%) BRAF-rearranged MIFS, but not in the BRAF-amplified case. Up-regulated VGLL3 mRNA expression was also demonstrated in the index case by RNA sequencing. The 7 BRAF-rearranged/amplified MIFS arose in the fingers (n=3), and 1 each in wrist, forearm, foot, and knee, of adult patients (36 to 74 y; M:F=4:3). The histologic spectrum ranged from predominantly solid growth of plump histiocytoid to epithelioid tumor cells with focal myxoid change to a predominantly myxoid background with scattered tumor cells. Varying degree of inflammatory infiltrates and large tumor cells with virocyte-like macronucleoli were observed in most cases. Immunohistochemical stains of phosphorylated ERK, a downstream effector of BRAF activation, were positive in all 4 cases tested (2 diffuse strong, 2 focal strong). Unlike t(1;10), BRAF rearrangements were only found in MIFS but not in 6 hemosiderotic fibrolipomatous tumor (HFLT) lacking TGFBR3-MGEA5 fusions (including 2 pure HFLT, 2 hybrid HFLT-MIFS, and 2 associated with pleomorphic hyalinizing angiectatic tumors).