Multifaceted Spindle Cell/Sclerosing Rhabdomyosarcoma With Role of Immunohistochemistry in Avoiding Misdiagnosis: A Multi-Institutional Study of 45 Distinct Tumors.

Background. Spindle cell/sclerosing rhabdomyosarcoma is a rare neoplasm and has an aggressive clinical course. Because of its rarity, we performed a multi-institutional collaboration to comprehend the overarching clinical, histopathological, and immunohistochemical characteristics of a cohort of spindle cell/sclerosing rhabdomyosarcoma. Materials and Methods. Forty-five patients with spindle cell/sclerosing rhabdomyosarcoma were identified. Demographics, clinical, histopathological, and immunohistochemistry data were reviewed and recorded. Results. The patients' age ranged from 1 to 85 years with a male to female ratio of 1.2:1. There were 15 children/adolescents and 30 adults. Eighteen (40%) tumors were located in the head and neck region. Twenty-four (53%) tumors displayed a bimorphic cellular arrangement with hypercellular areas having short, long, and sweeping fascicular and herringbone pattern, and hypocellular areas with stromal sclerosis and associated hyalinized and/or chondromyxoid matrix. Histomorphological differentials considered were leiomyosarcoma, malignant peripheral nerve sheath tumor, fibrosarcoma, nodular fasciitis, liposarcoma, synovial sarcoma, sarcomatoid carcinoma, solitary fibrous tumor, dermatofibrosarcoma protuberans, and schwannoma. Six tumors exhibited marked stromal sclerosis. The myogenic nature was confirmed by immunohistochemistry. Positivity for at least one skeletal muscle-associated marker (MyoD1 and/or myogenin) was observed. Conclusion. Spindle cell/sclerosing rhabdomyosarcoma diagnosis can be challenging as a number of malignant spindle cell neoplasm mimic this entity. Thus a correct diagnosis requires immunohistochemical work up with a broad panel of antibodies. In view of rarity of this neoplasm, further studies on a large cohort of patients with clinical follow-up data are needed for a better understanding of this tumor.

SS18-SSX Expression in a Contemporary Cohort of Primary Renal Synovial Sarcoma: A Multi-Institutional Experience of Fourteen Patients.

Primary renal synovial sarcoma is a rare aggressive mesenchymal neoplasm of the kidney that accounts for less than 1% of renal sarcomas. Herein, we describe the clinicopathologic and molecular findings of 14 renal synovial sarcoma patients in one of the largest case series to date and to our knowledge, the only renal synovial sarcoma series to use novel SS18-SSX IHC. Clinicopathologic, IHC, molecular, management, and follow-up data were reviewed and analyzed. Macroscopically, the tumors had either homogeneous, tan-white, and solid (n = 10), variegated and solid (n = 3), or variegated and solid-cystic (n = 1) cut surfaces. Spindle cell (n = 10), round cell (n = 3), and round to epithelioid morphologies (n = 1) were observed. SS18-SSX IHC was positive in all 14 tumors (diffuse, n = 10; multifocal, n = 2; focal, n = 2). All the tumors harbored SS18::SSX1/2 gene rearrangement. Metastases to the liver, brain, and lung (n = 1); liver and bone (n = 1); liver and diaphragm (n = 1) were identified. Adjuvant chemotherapy was administered in 11/12 patients. Follow-up was available for 10 patients (time period range: 5 to 24 months). Four patients died of disease, and six patients are alive with no recurrence or metastasis. As SS18-SSX IHC showed an excellent concordance with the FISH results, this may reliably be used in the IHC panel of spindle/round cell sarcomas of the kidney and as a molecular surrogate for renal synovial sarcoma, particularly in a resource-limited setting. Also, the tumors with focal SS18-SSX expression had lower break apart signals in the FISH assay (19% and 23% in two tumors with focal SS18-SSX IHC positivity).

Correlation of ROS1 (D4D6) Immunohistochemistry with ROS1 Fluorescence In Situ Hybridization Assay in a Contemporary Cohort of Pulmonary Adenocarcinomas.

Sambit K. MohantyObjective Repressor of Silencing ( ROS1 ) gene rearrangement in the lung adenocarcinomas is one of the targetable mutually exclusive genomic alteration. Fluorescence in situ hybridization (FISH), immunohistochemistry (IHC), next-generation sequencing, and reverse transcriptase polymerase chain reaction assays are generally used to detect ROS1 gene alterations. We evaluated the correlation between ROS1 IHC and FISH analysis considering FISH as the gold standard method to determine the utility of IHC as a screening method for lung adenocarcinoma. Materials and Methods A total of 374 advanced pulmonary adenocarcinoma patients were analyzed for ROS1 IHC on Ventana Benchmark XT platform using D4D6 rabbit monoclonal antibody. FISH assay was performed in parallel in all these cases using the Vysis ROS1 Break Apart FISH probe. Statistical Analysis The sensitivity, specificity, positive and negative likelihood ratios, positive and negative predictive values, and accuracy were evaluated. Results A total of 17 tumors were positive either by IHC or FISH analysis or both (true positive). Four tumors were positive by IHC (H-score range: 120-270), while negative on FISH analysis (false positive by IHC). One tumor was IHC negative, but positive by FISH analysis (false negative). The sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, positive predictive value, negative predictive value, and accuracy were 94.4% (confidence interval [CI]: 72.71-99.86%), 63.6% (CI: 30.79-89.07%), 2.6 (CI: 1.18-5.72), 0.09 (CI: 0.01-0.62), 80.95% (CI: 65.86-90.35%), 87.5% (CI: 49.74-98.02%), and 82.76%, respectively. Conclusion ROS1 IHC has high sensitivity at a cost of lower specificity for the detection of ROS1 gene rearrangement. All IHC positive cases should undergo a confirmatory FISH test as this testing algorithm stands as a reliable and economic tool to screen ROS1 rearrangement in lung adenocarcinomas.

PD-L1 expression and its clinicopathologic and genomic correlation in the non-small cell lung carcinoma patients: An Indian perspective.

BACKGROUND: Immunotherapy with checkpoint inhibitor programmed death-1 (PD-1) and programmed death-ligand 1 (PD-L1) antibodies targeting the cellular immune checkpoints is the present area of interest showing promising results in patients with advanced non-small cell lung cancer (NSCLC). As there is paucity of PD-L1 expression data from the Indian perspective, we studied the correlation of clinicopathologic profile and oncogenic driver mutations in these patients. MATERIALS AND METHODS: Samples from 252 advanced NSCLCs patients were studied for PD-L1 expression through immunohistochemistry using rabbit anti-human PD-L1 monoclonal antibody (clone SP263) on Ventana BenchMark ULTRA autostainer. Simultaneously, genetic mutations were studied by next generation sequencing (for EGFR, ALK, ROS, MET, and BRAF). PD-L1 expression was analyzed for association with clinicopathologic features and various mutations. RESULTS: PD-L1 positivity was seen in 134 patients (53.2 %). It was twice more prevalent in males than females. No significant correlation was observed between PD-L1 expression with age, gender, site of testing (primary vs. metastatic tumors), smoking status, tumor laterality, stage, or histologic type; however, there was significant difference among solid and acinar types of adenocarcinoma combined together vs. other adenocarcinoma subtypes (p = 0.013), and well and moderately differentiated vs. poorly differentiated tumors (p = 0.022). When types/extent of PD-L1 positivity (≥25 %) were compared with demographics, clinical, and pathologic variables, significant differences were observed across the tumor grades (high-grade vs. low-grade) (p = 0.009) and stages (p = 0.039). The PD-L1 expression failed to demonstrate any statistical significance with oncogenic drivers. High PD-L1 expression (TPS ≥ 50) was observed in 27.6 % patients, and it was more prevalent in female patients (32.4 %), aged ≥60 years (33.8 %), smokers (27.3 %), poorly differentiated (36.8 %) and stage IV tumors (28.2 %). Exon 19 deletion was more prevalent in PD-L1 negative tumors whereas exon 21 substitution (L858R) was seen more in PD-L1 positive tumors. CONCLUSIONS: This is the largest Indian study demonstrating PD-L1 expression in NSCLC patients comparing with clinicopathologic and genomic parameters. PD-L1 expression was significantly associated with high-grade, solid, and acinar types of adenocarcinoma and advanced tumors. High PD-L1 expression was more prevalent in female patients, aged ≥60 years, smokers, and poorly differentiated and stage IV tumors (28.2 %). Exon 19 deletion was more in PD-L1 negative tumors whereas exon 21 substitution (L858R) was more in PD-L1 positive tumors. PD-L1 is a potential predictive marker stratifying patients who benefit from PD-1 pathway-targeted therapy.

The utility of evaluating mismatch repair proteins in endometrial carcinoma: an experience from a tertiary referral centre in North India.

BACKGROUND: Endometrial cancer (EC) is a common gynecological malignancy. Around 25-30% patients have mismatch repair deficiency (MMRd). Lynch syndrome is caused by germline mutations in MMR genes. Lynch-associated tumours have better prognosis, however implications for prognosis and survival is less known. Microsatellite insufficiency (MSI) is associated with high neoantigen loads and number of tumor infiltrating lymphocytes, which overexpresses PD-1 and PD-L1 and are excellent candidates for PD-1-targeted immunotherapies. In this study, we aim to evaluate the utility of MMR in patients with EC and its clinico-pathological correlation. METHODS: Eighty-two cases of EC which underwent MMR evaluation over a period of five years at our centre were included. Demographics, clinical details including family history, histopathological and immunohistochemical (IHC) parameters were recorded. Tumors with loss-of at least one protein were considered MMR deficient (MMRd) and those with intact expression were MMR proficient (MMRp). RESULTS: Of 82 cases tested, 27 (33%) were MMRd. Frequencies of IHC MMR loss of expression were: MLH1/PMS2: 17 (21%), MSH6 loss only: 3 (4%), MSH2/MSH6 loss: 3 (4%), PMS2 loss: 2 (2%). In MMRd cases, most common histologic tumor type was endometrioid adenocarcinoma (70%). Loss of expression was significantly (p < 0.001) more frequent in lower uterine segment involvement and positive family history. CONCLUSIONS: MSI plays an important role in the progression of endometrial cancer. Lower uterine segment involvement and positive family history are significant predictor of MMR loss. Routine testing of MMR proteins in endometrial cancer can contribute to screening of Lynch syndrome families and make immunotherapy available as a treatment option.

Comparison of epidermal growth factor receptor mutation detection turnaround times and concordance among real-time polymerase chain reaction, high-throughput next-generation sequencing and the Biocartis Idylla™ platforms in non-small cell lung carcinomas.

OBJECTIVES: Activating mutations in the tyrosine kinase domain of the epidermal growth factor receptor (EGFR) gene of non-small cell lung carcinomas (NSCLC) can be targeted by the tyrosine kinase inhibitors. A number of molecular diagnostic platforms are used to detect actionable targets in the exon(s) 18, 19, 20, and 21 of the EGFR gene. The Idylla™ system (Biocartis, Mechelen, Belgium) is a relatively novel technique and is unique in integrating both sample processing and real-time polymerase chain reaction (RT-PCR) in a single cartridge. We sought to conduct this study to compare the turnaround time (TAT) and concordance of Idylla™ system with the conventional RT-PCR and next-generation sequencing (NGS) for EGFR mutation detection. METHODS: In this retrospective analysis, 38 formalin-fixed, paraffin-embedded NSCLC tissue blocks with known NGS results by Ion Torrent™ S5 NGS platform were retested by the RT-PCR and Idylla™ platforms. RESULTS: A total of 15 of 38 (39.4 %) tumors that showed various EGFR mutations by NGS and conventional RT-PCR techniques were subjected to the Idylla™testing. These cases satisfied the specimen adequacy criteria of at least 10 % tumor cells for the testing. The mutations detected by the NGS were also detected by the Idylla™ testing. However, NGS identified additional 3 mutations in 3 cases, involving T709 V (exon 18, n = 1) and V774 M (exon 20, n = 2). The tumors with wild type EGFR on NGS did not have any actionable mutation detected by the Idylla™. Average EGFR testing TAT by Idylla™ was only 7.2 h (4-12 hours), as compared to conventional RT-PCR taking 54 h (31-79 hours) and NGS requiring 10.7 days (7.1-14 days). The actual procedure time by conventional RT-PCR was 24 h, NGS was 6.5 days, and Idylla™ was only 3 h. CONCLUSIONS: In summary, the Idylla™EGFR testing is an efficient, rapid, and fairly simple tool that can be used in the routine molecular laboratory with limited expertise and infrastructure and using the lowest amount of tissue material.

Restrictive Dermopathy - A Rare Congenital Skin Disorder.

Restrictive dermopathy is a rare, autosomal recessive, lethal congenital skin disorder. This congenital genodermatosis could be mistaken for various other similar skin disorders. Diagnosis is a must in the context of genetic counseling for the subsequent pregnancy. We herein report a preterm male neonate with restrictive dermopathy, with additional feature of multiple bone fractures.

A rare case report of mixed olfactory neuroblastoma: Carcinoma with review of literature.

BACKGROUND: Olfactory neuroblastoma (ONB) is a rare malignant neuroectodermal tumor of the nasal cavity. Mixed olfactory neuroblastoma which contains areas of divergent differentiation is even rare. Till date, only 4 cases of mixed olfactory neuroblastomas have been reported. CASE DESCRIPTION: We report the case of a 46-year-old male who presented with the chief complaints of nasal bleeding and nasal obstruction since 4 months. Radiological imaging was suggestive of a large heterogeneous mass in the left superior nasal cavity with extensions into bilateral maxillary, ethmoidal, and sphenoidal sinuses, as well as into the anterior cranial fossa. Bifrontal osteoplastic craniotomy and excision of the intracranial part of the tumor from above and transnasal endoscopic removal of the mass in the nasal cavities and paranasal sinuses from below was done. Postoperative radiological imaging was suggestive of gross complete excision of the mass. Histopathological diagnosis was "mixed olfactory neuroblastoma-carcinoma (squamous and glandular differentiation) Hyams grade IV." On immunohistochemistry, the tumor cells were positive for neuron specific enolase (NSE), synaptophysin, chromogranin, and CD56 and peripherally for S100. Because of personal reasons, the patient did not take adjuvant radiotherapy. He presented again after 2 months with a full blown recurrence of esthesioneuroblastoma with similar extensions as before. The patient is now planned for salvage surgery followed by adjuvant chemoradiation. CONCLUSION: We report the 5th case in the world of mixed olfactory neuroblastoma-carcinoma with squamous and glandular differentiation. From an analysis of the findings in the 5 reported cases of mixed olfactory neuroblastomas, one might infer that a separate subcategory of ONB, i.e., mixed ONB, should be considered because mixed ONBs have an aggressive behavior, high rates of recurrence, and these tumors should be treated aggressively by multimodality treatment.

Intraocular Ependymoma With Blood-Filled Spaces: Neoplasm or a Reactive Process With Ependymal Differentiation-A Dilemma.

Intraocular glial lesions are rare and include retinal gliosis, hamartomas, and astrocytomas and rarely ependymomas. Ependymomas are slow-growing glial tumors preferentially arising in the central nervous system (CNS), occasionally presenting at sites outside the CNS, with only 2 cases of primary retinal ependymoma reported till date. We report herein the third such case of a 20-year-old male who presented with a painful blind eye. The enucleated specimen showed presence of a glial tumor with cells arranged in sheets as well as few true rosettes and pseudo-rosettes and an immunohistochemical profile similar to a classical ependymoma at usual sites in the CNS. Additionally, the presence of blood-filled spaces and few proliferating blood vessels made it a diagnostic challenge. All retinal glial lesions are positive for GFAP and S100. Therefore, immunostaining for EMA as well as the MIB-1-labeling index maybe vital in differentiating ependymomas from other intraocular glial lesions.