Significance of genetic analysis in adult patients with inherited chronic kidney disease.

Genetic focal segmental glomerulosclerosis (FSGS) is an important but underestimated cause of inherited proteinuric chronic kidney disease (CKD) in adults. We discuss a case of familial CKD due to inverted formin 2 (INF2) gene mutation, where three siblings had disparate phenotypic presentations ranging from CKD with subnephrotic proteinuria to nephrotic-range proteinuria with collapsing FSGS on kidney biopsy over a period of 8 years. The youngest sibling was the index case. The family agreed to undergo genetic testing only after two more siblings were diagnosed with kidney disease. This case highlights how clinical heterogeneity, absence of family history in the index case, initial lack of specific biopsy-proven diagnosis and reluctance to undergo genetic testing can delay the diagnosis of genetic kidney disease in adults.

Hepatic and perihepatic PEComas: A study describing a series of five rare cases.

BACKGROUND: Perivascular epithelioid cell tumors (PEComas) encompass a group of rare mesenchymal neoplasms, with dual melanocytic and muscular differentiation. Hepatic PEComas are rare and difficult to diagnose, and their behavior is still unclear. MATERIALS AND METHODS: Herein, we report a total of five cases of hepatic and perihepatic PEComas over a period of the last 5 years from our and collaborating center's archive. A detailed histological evaluation was done. A comprehensive panel of immunohistochemical stains was used and fluorescence in-situ hybridization analysis was performed for the TFE3 gene using break-apart probes. RESULT: All these patients were women, with an average age of presentation of 44 years. The lesions were in the right hepatic lobe: three cases, the left hepatic lobe: one case, and gastrohepatic ligament: one case. The preoperative clinicoradiological diagnoses were hepatocellular carcinoma (HCC), focal nodular hyperplasia, hemangioma, metastasis, and gastrointestinal stromal tumor, respectively. Surgical excision was performed in four cases with no further adjuvant therapy. Histopathological examination and subsequent immunophenotyping revealed a diagnosis of PEComa. Fluorescence in-situ hybridization analysis was performed for TFE3 gene rearrangement in four cases. CONCLUSIONS: This series highlights the fact that accurate histological diagnosis of hepatic or perihepatic PEComas is important to prevent unnecessary aggressive treatment, unlike primary hepatocellular carcinomas or hepatoid/epithelioid metastatic tumors.

Characterization of the novel HLA-B*15:05:01:02 allele by sequence-based typing.

HLA-B*15:05:01:02 differs from HLA-B*15:05:01:01 by one nucleotide change in intron 2 at position 517 (C > A).

One nucleotide substitution in the 3'UTR generated the novel allele HLA-B*40:01:02:47 in a North Indian individual.

HLA-B*40:01:02:47 differs from HLA-B*40:01:02:01 by one nucleotide change in the 3'UTR at position 2739 (A>T).

A single nucleotide substitution in intron 3 generated the novel HLA-A*11:01:01:68 allele.

HLA-A*11:01:01:68 differs from HLA-A*11:01:01:01 by one nucleotide change in intron 3 at position 1474 (G > A).

Demographic and clinical profile of 1106 adult soft tissue sarcoma patients: A single institutional prospective database experience from India.

BACKGROUND: Adult soft tissue sarcomas (STS) are rare and diverse. Current management is based on limited literature from the West. Therefore, data from different geographical regions is required, including the low-middle-income countries. This is our experience managing adult sarcomas in the tertiary cancer center of North India. MATERIALS AND METHODS: This is a retrospective analysis of the structured sarcoma database of patients treated in the surgical oncology department between 1992 and 2020. The descriptive analysis includes demography, site distribution, diagnosis, histopathology variations, prior surgical interventions, and stage. RESULTS: A total of 1106 soft tissue sarcoma patients were treated in three decades. Age distribution was 13%, 43%, 31%, and 11% in <20, 21-40, and 41-60 and >60 years, respectively. The male-to-female ratio was 1.73. The anatomical distribution was 17%, 42%, 23%, 7%, 7%, and 3% in upper extremity, lower extremity, trunk, retroperitoneum, head and neck, and viscera, respectively. Overall, 49% of patients had undergone prior suboptimal surgeries at community hospitals. Common histology subtypes were synovial sarcoma (18%), undifferentiated pleomorphic sarcoma (UPS) (13%), dermatofibrosarcoma protuberans (12%), and liposarcoma (9%). A pathological discordance of 13% was identified between the initial and the final histologies. Overall, 61% of tumors were high-grade. Memorial Sloan Kettering Stages II and III were present in 33% and 35% of patients, respectively. CONCLUSIONS: This is one of the largest single institutional experiences of STS from the Asian population. Mostly young adults were affected with male preponderance. The lower extremity and trunk were common subsites. Frequent histologies were synovial sarcoma and UPS. A high rate of suboptimal surgical intervention at the community level and pathological discordance was noted. This study highlights the need to establish prospective structured databases for capturing quality information related to rare malignancies and providing insights for future research.

Treatment outcomes in patients with Ewing sarcoma of the spine in a resource-challenged setting: 17-year experience from a single center in India.

Ewing sarcoma (ES) of the spine is a rare childhood cancer with sparse literature on treatment outcomes. We aimed to describe survival outcomes and prognostic factors in patients with spinal ES treated at a single institute in a resource-challenged setting. We conducted a retrospective analysis of patients with spinal ES registered at a tertiary care oncology center between 2003-2019. Clinical patient data was retrieved from hospital records. Cox regression analysis was used to identify the association of baseline clinical parameters with event free survival (EFS) and overall survival (OS). A cohort of 85 patients was analyzed including 38 (45%) patients with metastatic disease. The median age was 15 years with 73% being male. Local therapy was administered in 62 (72.9%) patients with surgery alone in 8 (9.4%), radiotherapy alone in 36 (42.4%) and both in 18 (21.2%) patients. A higher proportion of males received local therapy than females (80.3% versus 59.1%; p = 0.049). The median EFS and OS were 20.1 and 28.6 months, respectively. On univariable analysis, age ≤ 15 years, female sex, serum albumin ≤3.5 g/dL and hemoglobin ≤11 g/dL were associated with inferior EFS while younger age, female sex, hypoalbuminemia and metastatic disease were associated with inferior OS. On multivariable analysis, only hypoalbuminemia was predictive for inferior EFS (HR:2.41; p = 0.005) while hypoalbuminemia (HR:2.06;p = 0.033) and female sex (HR:1.83; p = 0.046) were associated with inferior OS. We concluded that hypoalbuminemia confers poor prognosis in ES spine. Survival outcomes are poorer in females treated in our setting, possibly due to prevailing sex-based biases.

Minimally invasive autopsy in the evaluation of fetal malformations and stillbirths: A feasibility study.

BACKGROUND: Minimally invasive autopsy (MIA) using post-mortem magnetic resonance imaging with ancillary investigations is reported as accurate as conventional autopsy. This study assesses MIA's feasibility and accuracy compared to conventional autopsy. METHOD: MIA and/or conventional autopsy were performed on malformed fetuses (14-20 weeks gestation) and stillbirths (>20 weeks gestation), with/without malformation. Concordance in diagnostic accuracy (95% confidence interval [CI]) and agreement (Kappa coefficient [k]) were assessed in malformed cases where both MIA and autopsy were conducted. RESULTS: We enrolled 200 cases, including 100 malformed fetuses (<20 weeks) and 100 stillbirths (with/without malformations). Concordance of 97.3% was observed between MIA and autopsy in 156 malformed cases. The overall diagnostic accuracy of MIA was 96.04%. CONCLUSION: While conventional autopsy remains the gold standard, MIA is feasible in tertiary care settings. It can be considered a potential alternative for post-mortem assessment, particularly in settings with limited facility of conventional autopsy and parental refusal.

Depth of Invasion in Carcinoma Tongue: Evaluation of Clinical and Imaging Techniques.

BACKGROUND: "Depth of invasion" is an additional index incorporated in 8th AJCC staging system for oral cavity squamous cell carcinoma based on its prognostic significance. Pre-operative assessment by clinical palpation and imaging modalities has been used with limitations. The aim of the study is to compare different techniques including clinical palpation, ultrasound, and magnetic resonance imaging with histopathology for assessment of depth of tumor invasion. MATERIALS: Fifty patients of carcinoma tongue (T1-T3) were enrolled. Clinical palpation, Ultrasound tongue, and Magnetic resonance imaging were used to assess depth of tumor invasion. Microscopic depth of invasion was considered as reference. Statistical analysis was done to assess the level of agreement, reliability, and internal consistency. ROC analysis was done to find the "Area Under Curve" for microscopic depth versus ultrasound, MRI, and gross histopathological "depth of invasion". RESULTS: Ultrasound tongue showed highest "area under curve", Intra class correlation (ICC:0.786) with a good consistency (Cronbach's Alpha:0.880) with histological reference compared to MRI(ICC:0.689;CA:0.816). Clinical palpation showed weak agreement (Kappa:0.43) for assessing depth. To observe the concordance between ultrasound and microscopic depth, Lin's Concordance Correlation Coefficient (CCC = 0.782) was calculated with 95% limits of agreement. Lin's concordance correlation between ultrasound and microscopic depth showed a good agreement. CONCLUSIONS: Ultrasound tongue is a reliable imaging modality for pre-operative T staging by assessing tumor "depth of invasion" in carcinoma tongue patients with good internal consistency as per 8th AJCC staging system. LEVEL OF EVIDENCE: 2 (CEBM-Level of Evidence-2.1) Laryngoscope, 134:215-221, 2024.

SMARCB1/INI1-Deficient Poorly Differentiated Carcinoma of the Colon With Rhabdoid Features-A Rare Tumor With Serrated Phenotype: Case Report and Review of Literature.

Poorly differentiated colonic carcinoma with rhabdoid features is a rarely described entity. Our knowledge regarding the molecular phenotype of the tumor is evolving. We herein report a similar tumor with rhabdoid differentiation identified in the splenic flexure, which on histological examination showed a poorly differentiated phenotype with epithelioid to spindled morphology, tumor giant cells, and rhabdoid differentiation. The tumor was mismatch repair-proficient, deficient of INI1/SMARCB1, KRAS mutated (A146×), BRAFV600E mutated (c.1799T > A), and NRAS wild-type, indicating serrated differentiation in the tumor. The patient died after 3.5 months post-surgery. INI1-deficient poorly differentiated carcinoma of the colon is a rare, aggressive colonic malignancy showing a serrated phenotype. Routine identification and subtyping are important keeping in mind the distinct tumor phenotype, resistance to conventional chemotherapy, and dismal prognosis.

An extremely rare case of recurrent pleomorphic myxoidliposarcoma with response to eribulin chemotherapy - A case report.

Pleomorphic myxoid liposarcoma (PML) is a newly recognized entity with aggressive clinical behavior and a tendency to recur. It has histological features of both myxoid and pleomorphic liposarcoma and lacks the molecular and structural chromosomal abnormalities associated with myxoid and pleomorphic liposarcoma. The data about their response to chemotherapy is quite sparse. We report a case of incidentally detected pleomorphic myxoid liposarcoma of the mediastinum in a 32-year-old gentleman. After resection and adjuvant chemotherapy with doxorubicin and ifosfamide, there was no evidence of residual disease at the end of treatment. During a routine follow-up 5 months later, he was found to have a recurrence of the disease with histological confirmation. He received a trabectedin given its activity in myxoid liposarcoma. However, he had toxicities and progression leading to its discontinuation. Subsequently, eribulin was started as the next line of therapy. After 4 cycles of chemotherapy, response assessment was suggestive of partial response, which is still maintained after 7 cycles of eribulin. This is the first report of this entity responding to a newer chemotherapy regimen.

Limb salvage of an infant with infantile fibrosarcoma using TRK inhibitor larotrectinib.

Infantile fibrosarcoma (IFS) is an extremely rare locally aggressive soft tissue tumour of childhood. Primary therapy involves complete surgical resection with or without chemotherapy. However complete surgical resection might not be feasible in all cases and so requires other modalities for further management. We report the case of a male infant from Bangladesh with a locally advanced IFS of the leg which was partially resected. The patient received adjuvant chemotherapy which was complicated by the development of chemotherapy-related veno-occlusive disease and had to be discontinued. Thereafter he was referred to our dedicated sarcoma oncology clinic in India for further management. The parents of the child refused amputation of the limb. The tumour tested positive for NTRK3-ETV6 gene fusion and after discussion in multidisciplinary clinic, targeted therapy using oral NTRK inhibitor larotrectinib was started. The patient had complete response at the end of 8 months of treatment with larotrectinib. This is the first report from the Indian subcontinent and we encourage that these children should be referred to specialist clinics for appropriate multidisciplinary management for best outcomes.

A phase II study of gemcitabine and docetaxel combination in relapsed metastatic or unresectable locally advanced synovial sarcoma.

Synovial sarcoma (SS) is one of the commonest non-rhabdomyosarcoma soft tissue sarcoma with limited treatment options in the relapsed and advanced settings. The combination of gemcitabine and docetaxel has demonstrated its role predominantly in leiomyosarcoma and pleomorphic sarcomas but has not been prospectively studied in SS. This trial assesses the efficacy, tolerability and quality of life (QoL) with this regimen in metastatic/unresectable locally advanced relapsed SS.Patients and methods This was a single-arm, two-stage, phase II, investigator-initiated interventional study among patients with metastatic or unresectable locally advanced SS who had progressed after at least one line of chemotherapy. Gemcitabine 900 mg/m2 on days 1 and 8 and docetaxel 75 mg/m2 on day 8 were administered intravenously every 21 days. The primary endpoint was 3-month progression-free rate (PFR); overall survival (OS), progression-free survival (PFS), overall response rate (ORR), safety and quality of life (QoL) constituted the secondary endpoints.Results Twenty-two patients were enrolled between March 2020 and September 2021 and the study had to be closed early due to slow accrual. The study population comprised of 18 (81.8%) patients with metastatic disease and 4 (18.2%) patients with locally advanced, unresectable disease. The most common primary sites of disease were extremity in 15 (68%) and the median number of lines of prior therapies received was 1 (range 1-4). 3-month PFR was 45.4% (95% CI 24.8-66.1) and ORR was 4.5%. Median progression-free survival (PFS) was 3 months (95% CI 2.3-3.6) and median OS was 14 months (95% CI 8.9-19.0). 7 (31.8%) patients experienced grade 3 or worse toxicities, including anemia (18%), neutropenia (9%) and mucositis (9%). QoL analysis demonstrated significant decline in certain functional and symptom scales, while financial and global health scales remained stable.Conclusion This is the first prospective study on the combination of gemcitabine and docetaxel performed specifically in patients with advanced, relapsed SS. Although the accrual of patients could not be completed as planned, the therapy did produce clinically meaningful outcomes and met its primary endpoint of 3-month PFR. This result, along with the manageable toxicity profile and stable global health status on QoL analysis, should encourage further studies.Trial registration This trial was prospectively registered under the Clinical Trials Registry of India on 26/02/2020 (Registration number: CTRI/2020/02/023612).

Fibro-Adipose Vascular Anomaly (FAVA): Not Another Vascular Anagram.

Background. Fibro-adipose vascular anomaly (FAVA) is a rare benign mesenchymal lesion. Characterized primarily by intramuscular vascular malformation with secondary overgrowth of other mesenchymal elements, particularly fibro-adipose tissue, the condition is sometimes complicated by nonspecific clinical and imaging features, causing diagnostic dilemma. Herein, we attempted to outline and correlate the clinical characteristics, imaging findings, and histopathological features of this unusual entity. Method. The study design was retrospective in nature. Computerized database of our institute was searched for tumors, and archived slides were reviewed. Pertinent clinical data including imaging findings and treatment details were also recovered for correlation. Result. Among total of 24 patients identified, mean age was approximately 16 years, with the presence of nearly equal gender distribution. Pain along with swelling was most common symptoms with the presence of movement limitation, in few. Most lesions were long-standing and anatomically confined to lower limb with no side predilection. Using imaging, the majority of the lesions were identified as vascular anomaly or venous malformation, with FAVA being a differential diagnosis in few lesions. However, in a couple of patients, likelihood of mesenchymal tumors was also suggested, radiologically. On histology, the lesions showed the presence of clustered back to back, abnormal thin-walled, variably dilated, blood-filled sac-like vessels amid skeletal muscle bundles, along with extensive fibro-adipose tissue and variably atrophic skeletal muscle bundles, at the periphery, diagnostic of FAVA. Conclusion. Owing to the presence of overlapping clinical and imaging features, FAVA is often misdiagnosed, causing dilemma in clinical management. Clinical, radiological, and histopathological correlation is thereby warranted for clinching the correct diagnosis.

Lessons learnt from the clinico-genomic profiling of families with Li Fraumeni syndrome at a tertiary care centre in North India.

Li Fraumeni syndrome (LFS) is an inherited cancer predisposition syndrome due to TP53 gene mutation. There is sparse literature on LFS in the Indian population. We conducted a retrospective study of patients diagnosed with LFS and their family members, registered at our Medical Oncology Department between September 2015 and 2022. 9 LFS families consisted of 29 patients diagnosed currently or historically with malignancies including 9 index cases and 20 first or second-degree relatives. Of these 29 patients, 7 (24.1%) patients developed their first malignancy before the age of 18 years, 15 (51.7%) were diagnosed between 18and and 60 years, and 7 (24.1%) were diagnosed at age more than 60 years. A total of 31 cancers occurred among the families, including 2 index cases who had metachronous malignancies. Each family had a median of three cancers (range 2-5); sarcoma (n = 12, 38.7% of total cancers) and breast cancer (n = 6, 19.3% of total cancers) being the commonest malignancies. Germline TP53 mutations were documented among 11 patients with cancers and 6 asymptomatic carriers. Of these nine mutations, the most common types were missense (n = 6, 66.6%) and nonsense (n = 2, 22.2%), and the commonest aberration was replacement of arginine with histidine (n = 4, 44.4%). Eight (88.8%) families met either classical or Chompret's diagnostic criteria and two (22.2%) satisfied both. Two (22.2%) families fit the diagnostic criteria prior to onset of malignancy in the index cases but were untested till the index cases presented to us. Four mutation carriers from three families are undergoing screening as per the Toronto protocol. No new malignancies have been detected so far during the mean surveillance duration of 14 months. The diagnosis of LFS has socio-economic implications for patients and their families. Delay in genetic testing misses out a crucial window wherein asymptomatic carriers could initiate surveillance in a timely fashion. Greater awareness on LFS and genetic testing in Indian patients is warranted for better management of this hereditary condition.

Formulation and validation of a baseline prognostic score for osteosarcoma treated uniformly with a non-high dose methotrexate-based protocol from a low middle income healthcare setting: a single centre analysis of 594 patients.

Introduction: The outcomes of osteosarcoma in low middle income countries (LMICs) are different due to patients presenting in advanced stages, resource constraints and the use of non-high-dose-methotrexate (HDMTX)-based regimens. This study derived and validated a prognostic score for osteosarcoma that integrates biologic and social factors and is tailored for patients from an LMIC setting using a non-HDMTX-based protocol. Materials and methods: A retrospective study including osteosarcoma patients enrolled for treatment at a single tertiary care centre in India between 2003-19 was conducted. Baseline biologic and social characteristics were extracted from medical records and survival outcomes were noted. The cohort was randomised into a derivation and validation cohort. Multivariable Cox regression was used to identify baseline characteristics that were independently prognostic for survival outcomes in the derivation cohort. A score was derived from the prognostic factors identified in the derivation cohort and further validated in the validation cohort with estimation of its predictive ability. Results: 594 patients with osteosarcoma were eligible for inclusion in the study. Around one-third of the cohort had metastatic disease with 59% of the patients residing in rural areas. The presence of metastases at baseline (HR 3.39; p<0.001; score=3), elevated serum alkaline phosphatase (SAP) >450 IU/L (HR 1.57; p=0.001; score=1) and baseline tumour size > 10 cm (HR 1.68; p<0.001; score=1) were identified to be independent factors predicting inferior event free survival (EFS) and were included in development of the prognostic score. Patients were categorized as low risk (score 0), intermediate risk (score 1-3) and high risk (4-5). Harrell's c-indices for the score were 0.682, 0.608 and 0.657 respectively for EFS in the derivation, validation and whole cohort respectively. The timed AUC of ROC was 0.67 for predicting 18-month EFS in the derivation, validation and whole cohorts while that for 36-month EFS were 0.68, 0.66 and 0.68 respectively. Conclusions: The study describes the outcomes among osteosarcoma patients from an LMIC treated uniformly with a non-HDMTX-based protocol. Tumor size, baseline metastases and SAP were prognostic factors used to derive a score with good predictive value for survival outcomes. Social factors did not emerge as determinants of survival.

68Ga-PSMA PET/CT Detecting Metastatic Lesion of RCC: Missed on 18F-FDG PET/CT.

ABSTRACT: Renal cell carcinoma (RCC) accounts for ~2% of global cancers and deaths. Survival depends on initial staging and shows poor survival rate in metastatic disease. CT and MRI are used for evaluating RCC, and PET/CT is used for metastatic disease assessment. We report a case of RCC, where both 18F-FDG and 68Ga-PSMA PET/CT showed increased uptake in liver metastatic lesions; however, a subhepatic peritoneal deposit showed uptake only in PSMA. Also, liver lesions were seen better in PSMA owing to lesser background uptake, suggesting a possibility of 68Ga-PSMA being a potential tracer for RCC evaluation.

Efficacy and tolerability of sorafenib in desmoid-type fibromatosis: A need to review dose.

BACKGROUND: Sorafenib is currently one of the recommended treatments for symptomatic patients with desmoid-type fibromatosis (DTF). In this study, we aim to assess the clinical efficacy and tolerability of sorafenib in DTF patients. METHODOLOGY: Patients aged>18 years with a histological diagnosis of DTF and who have received sorafenib were enroled in this prospective observational study. Demographic data, clinical profile, the initial dose of sorafenib, treatment-related toxicities, dose modifications, and responses were recorded. The primary objective was to assess the objective response rate (ORR). The secondary objectives were to evaluate progression-free survival (PFS), tolerability, and adverse effects of sorafenib. Response assessment was based on response evaluation criteria in solid tumours 1.1 criteria. Adverse effects were graded according to National Cancer Institute Common Terminology Criteria for Adverse Events version 5.0 criteria. Time to event was calculated by Kaplan-Meier analysis, and survival was compared by log-rank test. Univariate and multivariable cox regression analysis were used to find independent predictors of relapse. RESULTS: A total of 104 patients were enroled in the study. The median age of the study population was 32 (range, 18-81) years, and 66.35% of patients were females. On response assessment, ORR was 46.1% and stable disease was observed in 31.7% patients. ORR was higher in the appendicular site (51.7%) compared to the abdominal site (27.2%). PFS at 1 and 2 years was 86.6% (79.6-92.7%) and 73.7% (62.4-82.8%), respectively. Two-thirds (66.6%) of patients had already received some form of treatment. At the time of analysis, 70 (67.3%) patients were continuing sorafenib. Only 4.8% stopped sorafenib due to progression, 10.5% due to intolerable adverse effects, and 17.3% due to other reasons. The common treatment-related toxicities were hand-foot skin reaction (HFSR) (89.4%), fatigue (79.8%), alopecia (70.1%), and diarrhoea (48.0%). In the patients with a starting dose of ≥400 mg (48.0% of patients), discontinuation was necessitated in 12% of patients, and further dose reduction was required in 58%, while only about 13% required dose reduction or discontinuation at a starting dose of 200 mg (51.9% of patients). Responses were not compromised due to lower starting doses. CONCLUSIONS: Sorafenib has good activity in DTF, but it is associated with significant toxicity. The adverse effect profile is distinct in Indian patients with higher HFSR and alopecia. Due to the high rate of dose reduction/discontinuation with a starting dose of 400 mg, a starting dose of 200 mg may be recommended in Indian patients.

Insights into the medical management of gastrointestinal stromal tumours: lessons learnt from a dedicated gastrointestinal stromal tumour clinic in North India.

Background: The advent of molecular driver alterations has brought in a revolutionary transformation in the treatment landscape of gastrointestinal stromal tumour (GIST). However, there is a paucity of data regarding mutational testing prevalence and associated outcomes from India. Methods: It was a retrospective study. We reviewed the case records of all patients diagnosed with GIST in a tertiary care centre from 2015 to 2021. The clinicopathological, mutational analysis and treatment plans were recorded. The study cohort was characterised by descriptive statistics. Results: Our study included 120 patients with a median age of 53 years (range: 28-77), with a male preponderance of 2:1. The most common site of the primary was the stomach (50%), followed by the small intestine (37%), with 55.8% of the patients having disseminated disease at presentation with a predominance of liver metastasis (67%). The prevalence of mutational analysis among patients prior to referral was 4%. 60.8% of the patients at our clinic had mutational analysis performed, and unavailability of analysis in the rest was due to financial constraints (12.5%), exhaustion of tissue (7.5%), reluctance to repeat biopsy (4.1%) and low-risk patients. We report c-kit in the majority (52%), platelet-derived growth factor receptor (PDGFR) in 19.2% and wild type in 16.4% along with the rarer subtypes: succinate dehydrogenase (SDH)-deficient GIST in 10.9% and Neurotrophic tyrosine receptor kinase (NTRK) fusion in 1.3%. Four of the eight SDH-deficient GIST patients had germline mutations (50%). The knowledge of driver mutations led to a change of treatment in 39.7% (29/73), i.e. stoppage of tyrosine kinase inhibitor (TKI) in 3, switch of TKI in 23, increase in TKI dose in 2 and upfront surgery in 1. The most common change was the use of sunitinib and regorafenib in patients with SDH-deficient GIST. Conclusion: Our study is one of the largest comprehensive series describing the clinical and mutational profile of GIST from India. The mutation testing rates at primary care centres continue to be low. Despite the hurdles, a large percentage of our patients underwent molecular testing, aiding in therapeutic decision-making.