engleski

PULMONARY HISTIOCYTIC SARCOMA IN A YOUNG ADULT MALE

Histiocytic sarcoma (HS) is a rare haematological malignant neoplasm composed of cells showing morphologic and immunophenotypic evidence of histiocytic differentiation. HS usually affects the lymph nodes, the skin and the gastrointestinal tract, whereas HS arising in the lung has very rarely been reported. According to the WHO, HS should be regarded as an aggressive haematopoetic neoplasm with strong potential for systemic spread and a poor response to therapy. We report the case of a 24-year-old male who subfebrile for two months. Chest radiography revealed a mass shadow measuring 70 mm in diameter in the left lower lung lobe. Chest CT showed a lobulated solid tumor measuring 60 x 38 x 70 mm. No mediastinal lymph node metastasis or other organ metastases were observed. Blood tests showed no abnormal tumor markers. Bronchoscopy revealed a necrotic tumor obstructing the entry of left B9 bronchus. Pathohistological and cytological findings of tumor forceps and brush biopsy did not confirm the diagnosis. The patient underwent left lower lobe resection and mediastinal lymphadenectomy. Histologically, the tumor cells were mostly isolated single cells, and very often multinucleated giant cells could be seen. There were many mitoses, usually 2 to 5 per high power field, however, nucleoli were usually inconspicious. By using a lot of immunohistochemical stainings, mesothelial tumors, epithelial tumors and neuroendocrine tumors were excluded. Also, a negative staining was found for vascular and smooth muscle cell tumors. CD 68 staining within the tumor revealed nests and strands of positive cells, however, the majority of the cells only showed a punctuated cytoplasmic staining, no membranopositive staining. The CD 99 immunostain showed a few scattered positively stained cells within the tumor, however, the majority of tumor cells were unstained. There was a negative reaction to NCAM and bodoplanin. By HMB-45 the tumor was entirely negative, by a desmin stain, remnants of smooth muscle cells were positively stained, however, the tumor was negative. Based on the immunohistochemical staining pattern as well as the morphologic appearance of the tumor, the pathologists concluded that the best diagnosis in this quite complicated case was histiocytic sarcoma. In resected lymph nodes, tumor was not found. No adjuvant therapy was performed. The patient remained in remission after 56 months follow-up, since the resection of the tumor.

histiocytic sarcoma; lung; immunohistochemical stainings

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