Intranodal Hemorrhagic Spindle Cell Tumor with Amianthoid Fibers - Report of a Case with Emphasis to Mast Cell Reaction and D2-40 Expression

Aim: Intranodal palisaded myofibroblastoma (IPM) is a rare benign mesenchymal tumor restricted to the lymph nodes. Here, we report the case of a 44-year-old male patient with an IPM confined to the left laterocervical area. Case Report: After an accurate microscopic evaluation of morphological and histochemical stains, immunohistochemistry was performed for vimentin, smooth muscle actin vascular markers, S100 protein, D2-40, Ki67, lymphoid and melanoma markers, keratin and desmin on sections obtained from a paraffin-embedded surgical biopsy. Results: Spindle cell proliferation was positive for vimentin, smooth muscle cell actin and D2-40 and negative for the other markers. Low proliferative index, assessed by Ki67, was found. Based on morphological and irnmunohistochemical findings we diagnosed this case as intranodal palisaded myofibroblastoma and we highlighted a D2-40 expression in the tumor spindle cells. The presence of mast cells and their particular distribution inside the tumor are also, together with D2-40 expression, original findings of this study. No therapy was recommended after surgical and histopathological evaluation. The evolution of the patient was favorable with no other relapse following surgical removal of the lymphadenopathy. He has a normal life and no other changes of clinical and biological parameters were registered. Conclusion: To the best of our knolwedge, this is the first report regarding a D2-40-positive reaction in the spindle cells of intranodal palisaded myofibroblastoma. Thus, D2-40 could be added to the panel of antibodies used for immunohistochemical diagnosis of such types of tumors.