Clinicopathological Profile and Survival Outcomes in Patients with Localised Extremity Synovial Sarcomas.

AIMS: Synovial sarcoma is a rare but aggressive variant of soft-tissue sarcoma. Literature is sparse and reported mostly from the West. We analysed the clinical profiles and prognostic factors of extremity synovial sarcoma patients in order to study their clinical journey. MATERIALS AND METHODS: This was a retrospective analysis. All patients with extremity synovial sarcoma treated between 1992 and 2020 were included. Patients with metastases at presentation were excluded. A descriptive analysis of demographic and clinicopathological features of patients undergoing limb salvage surgery (LSS) or amputation was carried out. Overall survival and disease-free survival were calculated for the entire cohort as well as for the LSS and amputation groups. Factors prognostic for survival were identified. RESULTS: In total, 157 patients had localised extremity synovial sarcoma. Predominantly, young adults (median 31 years) and males (61%) were affected. Over 70% of patients presented after recurrence or unplanned surgeries. Sixty-seven per cent of tumours were >5 cm, 69% were deep and 23% involved bone. The limb salvage rate was 64%. In the LSS group, adjuvant radiotherapy and chemotherapy were given to 72% and 68% of patients, respectively. In the amputation group, 72% of patients received adjuvant chemotherapy. In a median follow-up of 59 months, 39.4% of patients had recurrences, the majority (61.2%) were systemic. Five-year overall survival and disease-free survival were 53.4% and 49.8%, respectively. Overall survival was 63.9% and 29.7% in the LSS and amputation groups, respectively. On multivariate analysis, tumour size, depth, omission of radiotherapy and bone invasion were found to be the adverse prognostic factors. CONCLUSION: This is one of the largest studies on extremity synovial sarcoma. Mostly males and young adults were affected. The limb salvage rate was 64%, despite most being referred after unplanned surgery. Almost 70% of patients received radiotherapy and chemotherapy. Overall survival was inferior in the amputation group. Tumour size >5 cm, depth and bone invasion were negative, whereas adjuvant radiotherapy was a positive prognostic factor for survival. Chemotherapy had no impact on survival.

A unique case of light chain (AL) amyloidosis masquerading as hypophosphatemic osteomalacia.

Light chain (AL) amyloidosis is the result of a clonal plasma cell disorder which causes organ damage by deposition of misfolded light chains. Kidney is a common site of amyloid deposition. Proteinuria, usually in nephrotic range and unexplained renal insufficiency are the main manifestations of renal injury. We report a unique case of renal involvement by AL amyloidosis masquerading as metabolic bone disease. 38 year old male patient presented with progressively increasing diffuse bony pains, low backache and proximal weakness of both lower limbs since two years. On investigation, he was detected to have hypophosphatemic osteomalacia due to renal phosphate loss which was fibroblast growth factor 23 (FGF23)- independent. He also had nephrotic range low molecular weight proteinuria. Renal biopsy to ascertain the aetiology revealed deposition of amyloid fibrils in the glomerular mesangium on electron microscopy. Its characterization by immunofluorescence (IF) was consistent with immunoglobulin light chain (AL) amyloidosis. In the absence of a demonstrable plasma cell clone on bone marrow biopsy, we made a diagnosis of monoclonal gammopathy of renal significance (MGRS). He was treated with chemotherapy following which there was symptomatic improvement and reduction in phosphaturia. This case describes a unique presentation of renal injury due to AL amyloidosis masquerading as hypophosphatemic osteomalacia. The aim of this report is to highlight that hypophosphatemia in adults is usually acquired and treatment of underlying etiology results in cure, unlike in children where genetic counseling and phosphate replacement is the mainstay of treatment.

Solitary fibrous tumour: a diagnostic challenge for the cytopathologist.

BACKGROUND: Solitary fibrous tumour (SFT) is an uncommon spindle cell tumour that can occur in a variety of locations. Cytological features of this tumour have only rarely been reported in the literature. We describe the cytomorphological features of SFT with an emphasis on diagnostic pitfalls. METHODS: We retrieved nine cases of histopathologically proven SFT. Three cases had sampling error with inadequate smears and, therefore, six cases with adequate cellularity were analysed for cytological findings. The cytomorphological features and the differential diagnoses on fine needle aspiration cytology (FNAC) are discussed. RESULTS: No definitive cyto-diagnosis of any of these cases was possible because of the morphological overlap with various soft tissue tumours and other tumour types. There was one false-positive case, in which the possibility of sarcoma was suggested due to the presence of scattered atypical cells. Cytologically, the smears from the SFTs showed spindle to plump cells embedded in metachromatically staining dense ropy collagen material. The cells usually had oval to spindle shaped nuclei, bland chromatin and wavy elongated pale staining cytoplasm. CONCLUSION: A diagnosis of SFT on cytology smears is challenging. Careful attention given to certain cytological features in an appropriate clinicoradiological setting and application of immunochemistry, including CD34 and CD99 immunostaining on cytological samples, can help in the diagnosis of SFT in some cases. It is important to consider cytological overlaps of this tumour in order to avoid false-negative or false-positive results.

Thyroid tuberculosis - role of PCR in diagnosis of a rare entity.

BACKGROUND: Tuberculosis is a rare cause of granulomatous thyroiditis, whose diagnosis may be difficult with routine cytopathology and staining for acid-fast bacilli (AFB). STUDY DESIGN: Amongst 7962 cases of various thyroid lesions subjected to fine needle aspiration cytology (FNAC) over a period of 12 years, 34 cases (0.43%) were found to have cytological features of granulomatous inflammation with or without necrosis, which could be due to tuberculosis, granulomatous thyroiditis or other causes of granulomatous inflammation such as sarcoidosis or fungal infections. DNA was extracted from the material available on May-Grünwald-Giemsa-stained smears from the archival material. PCR for Mycobacterium tuberculosis was performed for insertion sequence IS6110. RESULTS: The age of the patients ranged from 32 to 58 years (median 48 years); 24 were female and 10 male. FNAC from thyroid swellings showed epithelioid granulomas with giant cells and/or necrosis. Although acid-fast bacilli were only seen in smears in two cases, 19/34 (55.9%) showed the presence of 123 bp DNA band under ultraviolet transillumination. Five control cases were negative. CONCLUSION: Our study of archival cytological material illustrates the importance of PCR as a potentially useful tool for the detection of M. tuberculosis DNA from FNAC of thyroid lesions, which could provide an alternative for rapid diagnosis of thyroid tuberculosis in AFB-negative cases.