Braf mutation in interdigitating dendritic cell sarcoma: a case report and review of the literature

Abstract

Interdigitating dendritic cell sarcoma is an extremely rare tumor. The diagnosis is difficult and is based on clinical, pathological and immunohistochemical evaluation. Differential diagnosis includes melanoma, mesenchymal and hematological malignancies. The mainstay of treatment is surgery for limited disease and different chemotherapy combinations have been tested for advanced disease. No evidence from prospective trials is currently available. We report the case of a 59 year-old male patient who experienced axillary lymphadenopathy with initial diagnosis of large-cell lung cancer on tumor biopsy. He underwent surgical resection with radical intent. Pathological diagnosis of interdigitating dendritic cell sarcoma was obtained on surgical samples. Nine months after radical surgery, he experienced systemic recurrence of disease and underwent chemotherapy with epirubicin and ifosfamide for 4 courses. During chemotherapy, he developed brain disease progression and underwent whole-brain radiotherapy. Systemic progression was then observed and molecular characterization was performed. B-RAF evaluation resulted positive for V600E mutation and the patient was treated with Vemurafenib according to molecular findings. He thus obtained initial clinical benefit but eventually died of brain hemorrhage. In conclusion, we report a case of B-RAF mutation detected in an interdigitating dendritic cell sarcoma patient treated with targeted therapy. B-RAF pathway could have a role in pathogenesis and evolution of this rare disease and could open new perspectives of treatment

Expression of enhancer of zeste homolog 2 (EZH2) protein in histiocytic and dendritic cell neoplasms with evidence for p-ERK1/2-related, but not MYC- or p-STAT3-related cell signaling

“…44 MYC was identified as a TCF4-activated gene, but not EZH2, p-ERK1/2, or p-STAT3. 38 These findings support our hypothesis that the mechanism of oncogenesis may differ in at least some cases of blastic plasmacytoid dendritic cell neoplasm compared with other histiocytic and dendritic cell neoplasms, and may be related to MYC expression.…”

Interdigitating dendritic cell sarcoma presenting in the sigmoid colon mesentery

“…Histological and immunohistochemical findings act perform key roles in the diagnosis of IDCS. Histologically, IDCS is characterized by the proliferation of spindle cells with whorled growth pattern, [ 14 ] which is usually absent in melanoma, malignant peripheral nerve sheath tumor, atypical fibroxanthoma, malignant fibrous histiocytoma, rhabdomyosarcoma, and leiomyosarcoma. [ 9 ] Immunologically, IDCS is almost uniformly positive for S-100 protein expression.…”

“…The results of therapy are unsatisfactory; the median survival for IDCS is 9 months. [ 14 ] Surgical resection remains the primary treatment for localized and resectable IDCS; adjuvant radiotherapy does not significantly improve overall survival or lower the recurrence rate. [ 2 ] Systemic chemotherapy is the mainstay of treatment for the patients with distant metastases.…”

Novel putative drivers revealed by targeted exome sequencing of advanced solid tumors

“…It is unclear what effect this mutation may have on sensitivity to RAF inhibitors such as vemurafenib. BRAF mutations have been described in follicular and dendritic cells sarcomas [ 78 , 79 ].…”