Scapular Angiomatoid Fibrous Histiocytoma with EWSR1-CREB1 Fusion in an Adult Patient

Background. Angiomatoid fibrous histiocytoma (AFH) is a rare intermediate malignant tumor that arises mainly in soft tissues, especially in the superficial extremities of patients younger than 30 years. There have been a few reports of AFH arising from sites other than soft tissue, including bone, and unusual site and age make it difficult to diagnose this rare tumor. Case Presentation. Here, we present a case of a 54-year-old man who was examined for chest pain, and computed tomography (CT) incidentally detected a bone tumor at the scapula with destruction of cortical bone and invasion into soft tissue. Magnetic resonance imaging revealed multiple cystic components with fluid-fluid levels. FDG-PET showed uptake at the axillary lymph node. The CT-guided needle biopsy revealed spindle cell sarcoma on histopathology. After neoadjuvant chemotherapy, a scapulectomy was performed. The final postresection histopathological diagnosis was the same as the preoperative diagnosis, and no obvious chemotherapeutic effect was observed. Next-generation sequencing of RNA isolated from paraffin-embedded tumor tissue revealed that these lesions harbored the EWSR1-CREB1 fusion gene, and the tumor was diagnosed as AFH. C-reactive protein level, which was elevated preoperatively, decreased after the operation, and there was no recurrence or metastasis 5 years after the treatment. Conclusion. The diagnosis of AFH is difficult when the tumor has an atypical presentation. Comprehensive genomic analysis, especially RNA sequencing, is efficient in diagnosing this rare tumor. Moreover, magnetic resonance imaging findings identical to AFH in soft tissue, the presence of paraneoplastic symptoms such as elevated inflammatory markers, and lymph node swelling were clues towards suspecting this tumor.

Angiomatoid Fibrous Histiocytoma: Case Presentation with Review of Literature

Angiomatoid fibrous histiocytoma is a rare neoplasm with an intermediate malignant potential, that mostly occurs in the subcutis and features varying proportions of epithelioid, ovoid and spindle cells in a nodular and syncytial growth pattern, with hemorrhagic pseudovascular spaces. Here, we report the clinical case of a 68-year-old man who presented with AFH on the right arm; the disease relapsed a few years after surgical excision. We also conduct a brief review of the literature, focusing on the biological and genetic characteristics and the differential diagnosis from other more or less similar entities.

Tocilizumab Controls Paraneoplastic Inflammatory Syndrome but Does Not Suppress Tumor Growth of Angiomatoid Fibrous Histiocytoma

Angiomatoid fibrous histiocytoma (AFH) is a rare soft tissue tumor that rarely metastasizes but lacks effective systemic therapy once it propagates. In some reports, high interleukin-6 (IL-6) production promotes tumor growth by autocrine stimulation and tocilizumab, an IL-6 receptor antagonist, can control AFH growth. Here, we present a case report on a patient with local recurrence and distant lymph node metastasis of AFH treated with tocilizumab. As a result, the inhibition of the IL-6 signaling pathway controlled paraneoplastic inflammatory syndrome (PIS); however, the local recurrent tumor progressed. This case implied that IL-6 is not necessarily the cause of tumor growth in AFH. Therefore, physicians should bear in mind that watchful observation is needed whether tocilizumab can control tumor progression despite the amelioration of PIS associated with the attenuated effect of IL-6 on AFH.

PD-L1 expression in angiomatoid fibrous histiocytoma

Angiomatoid fibrous histiocytoma (AFH) is a rare tumor of intermediate malignancy. Treatment options for unresectable and/or metastatic tumors are very limited. Immunotherapy with PD-1/PD-L1 inhibitors may be worth exploring. The aim of this study was to evaluate the expression of PD-L1 in AFHs. PD-L1 expression was assessed on 36 AFHs from 36 pediatric patients by immunohistochemical staining of PD-L1 (clone 22C3). Positivity was defined as membranous expression in ≥ 1% of either tumor or immune cells. The correlations between PD-L1 expression and clinicopathologic features were assessed. Two patients had lymph node metastasis. All patients underwent surgical resection; three of them also had systemic chemotherapy. Three patients had recurrence after initial resection; all patients were alive with a median follow-up of 2.5 years. Overall, twenty-two (61%) tumors were positively stained for PD-L1 and positivity was seen on both tumor and immune cells in eighteen of the 22 tumors. A positive correlation was found between tumor cell PD-L1 expression and CD8+ T-cell infiltration. There were no statistically significant differences between the status of PD-L1 expression and the clinicopathological features assessed. PD-L1 expression was identified in 61% of AFHs with a predominantly adaptive pattern. Our findings provide a rationale for future studies evaluating the potential of checkpoint immunotherapy for patients with unresectable and/or metastatic tumor.

Intracranial temporal bone angiomatoid fibrous histiocytoma: illustrative case

BACKGROUNDAngiomatoid fibrous histiocytoma (AFH) is a rare, slowly progressive neoplasm that most commonly occurs in soft tissues. AFH rarely occurs in bone such as the calvaria. The authors present a case of AFH in the petrous temporal bone, which, to their knowledge, is the first case of AFH in this location.OBSERVATIONSA 17-year-old girl presented with worsening positional headaches with associated tinnitus and hearing loss. Imaging demonstrated an extraaxial mass extending into the right cerebellopontine angle, with erosion of the petrous temporal bone, with features atypical for a benign process. The patient underwent retrosigmoid craniotomy for tumor resection. Pathology was consistent with a spindle cell tumor, and genetic testing further revealed an EWSR1 gene rearrangement, confirming the diagnosis of AFH. The patient was discharged with no complications. Her symptoms have resolved, and surveillance imaging has shown no evidence of recurrence.LESSONSThe authors report the first case of AFH in the petrous temporal bone and only the second known case in the calvaria. This case illustrates the importance of the resection of masses with clinical and imaging features atypical of more benign entities such as meningiomas. It is important to keep AFH in the differential diagnosis for atypical masses in the calvaria and skull base.