Chondroblastic osteosarcoma of the proximal left tibia in the setting of cystic fibrosis related diabetes mellitus. Clinical case

Abstract

Cystic fibrosis related diabetes (CFRD) is a rare pathology that combines genetically determined systemicity with damage to the exocrine glands, which leads to early manifestations of the disease, a clear exacerbation and chronicity of the process, with possible complications in bone remodeling with the occurrence of malignant tumors. Purpose - to acquaint practitioners with the peculiarities of manifestations, diagnosis and course of chondroblastic osteosarcoma in a child with CFRD. Features of the clinical course and differential diagnosis are described and given osteosarcoma of the proximal part of the left tibia against the background of CFRD in a child. The main diagnostic value of history, clinical picture, laboratory, instrumental, immunohistochemical and microscopic research methods was highlighted, in particular, a biopsy of this tumor. Microscopic examination of tissue biopsy revealed alternating areas of atypical cartilaginous tissue corresponding to the structure of chondrosarcoma 1-2 cm, solid proliferates of atypical fibroblast-like cells and areas of atypical and fibroblastic tissue containing elements of atypical osteogenesis. Periosteally - randomly oriented bone fragments at the place of the cortical plate, as well as impressions of the lower metaphysis of the thigh and the upper metaphysis of the tibia, near the knee joint. The immunohistochemical examination showed a clear differential diagnosis of the existing CD99-positive tumor cells (DAKO, clone 12E7). Some cells were positive for SATB2 (Cell Marque, clone EP281); tumor cells were negative for S-100 - SOX-10. The histological picture and immunophenotype of the tumor cells correspond to chondroblastic osteosarcoma. Osteosarcoma with genetic, metabolic and aplastic features developing in the setting of a comorbid background significantly complicates diagnosis and requires certain changes in the treatment tactics of CFRD (correction of prophylactic and basic therapy, metabolic and toxic disorders, including those caused by chemotherapy). The research was carried out in accordance with the principles of the Helsinki Declaration. The informed consent of the patient was obtained for conducting the studies. No conflict of interests was declared by the authors.