Background and Objectives: Tenosynovial giant cell tumors (TSGCTs) are benign soft tissue tumors that are divided into localized- and diffuse-type tumors, according to the World Health Organization classification of soft tissue tumours. The diffuse-type TSGCT sometimes behave aggressively and poses treatment challenges especially in patients with neurovascular involvement. Symptomatic patients who are not good candidates for surgery due to high morbidity risk may benefit from medical therapy. Objectives: Drugs that target programmed death ligand 1 (PD-L1) are among a new generation of medical therapy options, which, recently, have been explored and have displayed promising results in various cancer types; therefore, we aimed to investigate the PD-L1 status of TSGCTs as a possible therapeutic target. Materials and Methods: We assessed the PD-L1 status of 20 patients (15 men and 5 women, median age = 39 years) that had been diagnosed with TSGCTs in a single institution, between 2018 and 2020. The patients had localized- (n = 7) and diffuse-type (n = 13) TSGCTs. Formalin-fixed paraffin-embedded (FFPE) blocks were retrospectively retrieved from the pathology department. An immunohistochemical analysis was performed in sections of 3 micron thickness from these blocks. Results: Seventy-five percent of our patients with TSGCTs were immunopositive to PD-L1 staining. Conclusions: Taking into consideration the high positivity rate of PD-L1 staining in TSGCTs, PD-L1 blockage may be used as a valuable medical treatment for TSGCTs; however, further studies are needed.

Aim: Spindle cell lipoma is a rare tumor. Although located subcutaneously, they are localized in the posterior neck, shoulder, and lumbar regions. It can radiologically mimic liposarcoma. It is important to differentiate spindle cell lipoma from atypical lipomatous tumors. In this study, we aimed to present our studies on our patients with spindle cell lipoma with histopathological and clinical findings and give brief information about the differential diagnosis of this rare lipomatous lesion. Material and Methods: A total of 29 patients (27 male, 2 female) who underwent surgical treatment for spindle cell lipoma between January 2015 and December 2020 were included in this retrospective study. All patients were presented with mass lesions, and preoperative biopsy was performed in cases with low-fat content mass lesions. Results: The mean age of the patients was 57.0±14.6 (range, 25-79) years and the mean follow-up period was 25.0±8.6 (range, 6-47) months. No additional disease was detected in the patients. Marginal resection was preferred in 5 (17.2%) patients with lesions close to neurovascular structures. Wide resection was performed in the other 24 (82.8%) patients. CD34 was positive in all lesions. In one patient, CDK4 was positive, and the diagnosis was made as atypical spindle cell lipoma. At the last follow-up, there was no complication and recurrence in any of the cases. Conclusion: Spindle cell lipomas should be regarded in the differential diagnosis of lipomatous tumors. Local excision with negative margins may prevent a recurrence. Correct histopathologic differentiation from liposarcoma is of paramount importance for appropriate treatment.

Background and objectives: The COVID-19 pandemic has had a negative impact on healthcare in musculoskeletal pathology. There is no standard protocol for pathology services during a pandemic. The study aimed to assess the impact of COVID-19 restrictions on the workload of the musculoskeletal pathology service and the hurdles faced in collaboration with the orthopedic oncology unit in a tertiary reference center in a developing country. Materials and methods: The pathology reports from mid-March to mid-June 2019, 2020, and 2021 were retrospectively reviewed. Results: Significant differences were found between the pandemic period (2020) and the non-pandemic periods (2019-2021) in benign bone and soft tissue lesions, resection surgeries, and soft tissue tumors, which were more prevalent in the non-pandemic periods. However, there was no significant decrease in biopsy procedures. Conclusion: During the pandemic period, the biopsy procedure appears to be feasible for bone and soft tissue lesions without the need for anesthesia.