Journal of Clinical and Diagnostic Research. 2022 Mar, Vol-16(3): EC05-EC07 5 5 DOI: 10.7860/JCDR/2022/50794.16072 Original Article Pathology Section Fine Needle Aspiration Cytology of Giant Cell Tumour of Tendon Sheath INTRODUCTION Giant Cell Tumour of Tendon Sheath (GCTTS) are benign, solitary, slow growing soft tissue tumours commonly affecting the hands. They are also known as fibrous histiocytoma of synovium, pigmented nodular tenosynovitis, tenosynovial giant cell tumour, localised nodular tenosynovitis, benign synovioma, and fibrous xanthoma of synovium [1]. The common age group affected is 30 to 50 years with a female preponderance [2]. These tumours occur more frequently on upper limbs, especially hands (77%). They are the second commonest tumour of hands following simple ganglion cyst [3]. Other locations are spine, elbow, hip, knee, ankle and feet [4-6]. The diffuse form, also called pigmented villonodular synovitis occurs in younger age group and involves larger joints such as knee, elbow and ankle [5]. Fine Needle Aspiration (FNA) is usually performed to evaluate such superficially located lesions and carries the advantage of offering quick results, following which a complete surgical excision is planned. The study aimed to describe the various cytomorphologic findings in cases of GCTTS and their histopathological features wherever available. MATERIALS AND METHODS All cases of GCTTS diagnosed over a period of three years, from January 2015 to December 2017 in the Department of Pathology, ESI Hospital, Delhi, India, were reviewed. A total of 205 cases of soft tissue tumours were retrieved from the archives which included 12 cases of GCTTS. Retrospective analysis of these 12 cases was done in December 2019. Clinical details such as age, gender, tumour location, presentation and size were noted. FNAC was performed using 22-gauge needle attached to a 10 mL syringe. Smears were air dried and stained with Giemsa stain. Half of the swellings were subjected to histopathologic examination as well. Slides were prepared following routine tissue processing and subsequently stained with Hematoxylin and Eosin stain (H&E) stain. STATISTICAL ANALYSIS Descriptive statistics were used for analyses of the cases. RESULTS Twelve cases of GCTTS were retrieved and studied. These included 8 (66.67%) women and 4 (33.33%) men with male to female ratio of 1:2. The age at presentation ranged from 22 to 68 years with mean age of 39 years. The most common clinical presentation included painless, solitary, slowly progressive swelling over a finger, X-ray films revealed mild erosion of the underlying bone in two cases [Table/Fig-1,2]. SONAM JAIN 1 , SAUMYA NANDA 2 , MALVIKA SHASTRI 3 , ANNU NANDA 4 , VAIBHAV GARG 5 Keywords: Haemosiderin laden macrophages, Multinucleated giant cells, Small joints ABSTRACT Introduction: Giant Cell Tumour of Tendon Sheath (GCTTS), also known as localised nodular tenosynovitis, is a slow growing benign soft tissue tumour arising from synovium of tendon sheath, bursa or joint. Clinically, the lesions occur as skin-coloured nodules typically on the extremities. These tumours occur more frequently on the upper limbs especially hands (77%) where they form the second most common tumour following simple ganglion cyst. Aim: To describe the cytomorphologic findings in GCTTS and their histopathological features. Materials and Methods: This retrospective study was conducted at Department of Pathology, ESI Hospital, Delhi, India, in 12 diagnosed GCTTS cases for their cytological features from January 2015 to December 2017. Fine Needle Aspiration Cytology (FNAC) was performed with a 22-gauge needle attached to a 10 mL syringe. Smears were air-dried and stained with Giemsa stain. Cytomorphology of all the selected cases were analysed and descriptive statistics were used to evaluate the cases. Results: A total of 12 cases of GCTTS were retrieved. Diagnosis of GCTTS was made by FNAC in all the cases and confirmed by histopathological examination in half of the cases. The mean age of presentation was 39 years. Of these, 8 (66.67%) were women and 4 (33.33%) were men. The lesions were found most commonly over the index finger (n=5) followed by the ring finger (n=3), thumb (n=2), middle finger (n=1) and little finger (n=1). The most frequent clinical presentation was a painless, nodular, slow growing firm swelling over the finger. FNAC revealed cellular smears with few clusters and numerous scattered stromal cells along with interspersed multinucleated giant cells. Conclusion: A definitive preoperative diagnosis of GCTTS obtained through FNAC helps in formulating appropriate treatment plan. Histopathologic examination will confirm the cytological diagnosis and can help to predict recurrence by providing information on the resection margin, any satellite nodules, variable cell types and mitotic activity. [Table/Fig-1]: Mass over left proximal ring finger; [Table/Fig-2]: Posterioanterior radiograph of the same patient as in [Table/Fig-1], showing soft tissues shadow and scalloping of the shaft of bone of left ring finger. (Images from left to right)