Objective: Distribution of connective tissue tumors (CTTs) by histological subtypes can vary between geographic regions. Reports on this topic from the Middle East are scarce. We analyzed the distribution of CTTs by World Health Organization classification category and degree of malignancy in a Cancer Center in Oman.
Methods: Patients with histopathological diagnosis of a Connective Tissue Tumor (CTT) assisted in the Rare Tumors Program, SQCCCRC from 08.10.2021 to 20.06.2024 were eligible. We included patients with at least one consultation in our Center and excluded those with rare tumors other than CTT. We retrieved histopathological diagnoses from electronic clinical charts and grouped them according to the World Health Organization 2020 classifications of Soft Tissue and Bone Tumors by category and degree of malignancy. We used R software for summary statistics.
Results: Out of 322 potentially eligible patients, two hundred met the eligibility criteria. Of them, 84.5% had soft tissue sarcomas (66.0% trunk and extremity and 18.5% visceral respectively) and 15.5% bone tumors. Among soft tissue CTTs, Fibroblastic/Myofibroblastic accounted for 27.7 of cases, Adipocytic 18.7 %, Gastrointestinal Stromal Tumors 18.1%, Tumors of Uncertain Differentiation 18.1%, Smooth Muscle 6.0%, Vascular 4.2%, Peripheral Nerve tumors 3.6%, Skeletal Muscle 1.8%, So-called Fibrohistiocytic 1.2%, and Undifferentiated small round cell sarcoma of soft tissue 0.6%. Among bone CTTs, Undifferentiated small round cell sarcoma of bone represented 48.4 %, Osteogenic 22.6 %, Giant cell-rich 9.7 %, Notochordal 9.7 %, Chondrogenic 6.5%, and Vascular sarcomas 3.2%. Of soft tissue tumors, 68.0% were malignant, 26.9% were of intermediate malignant potential, 4.6% benign, and 0.5% had an unknown degree of malignancy. Of bone tumors, 87.1% were malignant, 9.7% intermediate, and 3.2% benign.
Conclusion: In our study, the distribution of CTT by WHO category was different compared to the reports from Europe and China. Our results can potentially contribute to general knowledge, care, and research.
