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.

Evaluation of programmed cell death ligand 1 expression in a contemporary cohort of penile squamous cell carcinoma and its correlation with clinicopathologic and survival parameters: A study of 134 patients.

OBJECTIVES: Penile squamous cell carcinomas (PCs) are rare malignancies with a dismal prognosis in a metastatic setting; therefore, novel immunotherapeutic modalities are an unmet need. One such modality is the immune checkpoint molecule programmed cell death ligand 1 (PD-L1). We sought to analyze PD-L1 expression and its correlation with various clinicopathologic parameters in a contemporary cohort of 134 patients with PC. METHODS: A cohort of 134 patients with PC was studied for PD-L1 immunohistochemistry. The PD-L1 expression was evaluated using a combined proportion score with a cutoff of 1 or higher to define positivity. The results were correlated with various clinicopathologic parameters. RESULTS: Overall, 77 (57%) patients had positive PD-L1 expression. Significantly high PD-L1 expression was observed in high-grade tumors (P = .006). We found that 37% of human papillomavirus (HPV)-associated subtypes and 73% of other histotype tumors expressed PD-L1, while 63% of HPV-associated tumors and 27% of other histotype tumors did not (odds ratio, 1.35; P = .002 when compared for HPV-associated groups vs all others). Similarly, PD-L1-positive tumors had a 3.61-times higher chance of being node positive than PD-L1-negative tumors (P = .0009). In addition, PD-L1 high-positive tumors had a 5-times higher chance of being p16ink4a negative than PD-L1 low-positive tumors (P = .004). The PD-L1-positive tumors had a lower overall survival and cancer-specific survival than PD-L1-negative tumors. CONCLUSIONS: Overall, PD-L1 expression is associated with high-grade and metastatic tumors. Lower PD-L1 expression is observed more frequently in HPV-associated (warty or basaloid) subtypes than in other, predominantly HPV-independent types. As a result, PD-L1 positivity, including higher expression, portends lower overall and cancer-specific survival. These data provide a rational for further investigating PD-L1-based immunotherapeutics in PC.

Papillary cystadenoma of the major salivary gland: A case report and review of literature.

Papillary cystadenoma (PC) of the salivary gland is an uncommon benign epithelial neoplasm that shows predominantly multicystic growth pattern with intraluminal papillary proliferation and areas of oncocytic differentiation. We report a case of papillary cystadenoma of the parotid gland in a 44-years-old female. The patient presented with painful nodular swelling in the right parotid region for two months. Ultrasonography revealed a well marginated oval lesion with altered signal intensity involving the superficial lobe. The excision specimen showed a neoplasm with multicystic spaces having papillary projections lined by benign low-grade epithelium and supported by fibrovascular cores. No significant cytological atypia or mitosis was observed. The cells were immunoreactive for Keratin, Keratin 7, and were negative for Keratin 20, AR, HeR2/neu, TTF1, CDX2, and GATA3. p63 and Keratin 5/6 highlighted the myoepithelial cell layer lining the cystic spaces as well as the papillary projections. The Ki-67 proliferation index was 6%. The patient is on close clinical and imaging follow-up for the last 1year and 8 months without any evidence of disease recurrence or metastasis. Rarity of the lesion and distinct histomorphology warrants appropriate knowledge and discussion of the subject.

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).

Reporting Trends, Practices, and Resource Utilization in Neuroendocrine Tumors of the Prostate Gland: A Survey among Thirty-Nine Genitourinary Pathologists.

Background. Neuroendocrine differentiation in the prostate gland ranges from clinically insignificant neuroendocrine differentiation detected with markers in an otherwise conventional prostatic adenocarcinoma to a lethal high-grade small/large cell neuroendocrine carcinoma. The concept of neuroendocrine differentiation in prostatic adenocarcinoma has gained considerable importance due to its prognostic and therapeutic ramifications and pathologists play a pivotal role in its recognition. However, its awareness, reporting, and resource utilization practice patterns among pathologists are largely unknown. Methods. Representative examples of different spectrums of neuroendocrine differentiation along with a detailed questionnaire were shared among 39 urologic pathologists using the survey monkey software. Participants were specifically questioned about the use and awareness of the 2016 WHO classification of neuroendocrine tumors of the prostate, understanding of the clinical significance of each entity, and use of different immunohistochemical (IHC) markers. De-identified respondent data were analyzed. Results. A vast majority (90%) of the participants utilize IHC markers to confirm the diagnosis of small cell neuroendocrine carcinoma. A majority (87%) of the respondents were in agreement regarding the utilization of type of IHC markers for small cell neuroendocrine carcinoma for which 85% of the pathologists agreed that determination of the site of origin of a high-grade neuroendocrine carcinoma is not critical, as these are treated similarly. In the setting of mixed carcinomas, 62% of respondents indicated that they provide quantification and grading of the acinar component. There were varied responses regarding the prognostic implication of focal neuroendocrine cells in an otherwise conventional acinar adenocarcinoma and for Paneth cell-like differentiation. The classification of large cell neuroendocrine carcinoma was highly varied, with only 38% agreement in the illustrated case. Finally, despite the recommendation not to perform neuroendocrine markers in the absence of morphologic evidence of neuroendocrine differentiation, 62% would routinely utilize IHC in the work-up of a Gleason score 5 + 5 = 10 acinar adenocarcinoma and its differentiation from high-grade neuroendocrine carcinoma. Conclusion. There is a disparity in the practice utilization patterns among the urologic pathologists with regard to diagnosing high-grade neuroendocrine carcinoma and in understanding the clinical significance of focal neuroendocrine cells in an otherwise conventional acinar adenocarcinoma and Paneth cell-like neuroendocrine differentiation. There seems to have a trend towards overutilization of IHC to determine neuroendocrine differentiation in the absence of neuroendocrine features on morphology. The survey results suggest a need for further refinement and development of standardized guidelines for the classification and reporting of neuroendocrine differentiation in the prostate gland.

Thrombotic Microangiopathy Secondary to Pancreatitis: A Diagnostic Enigma.

The association between thrombotic microangiopathy (TMA) and pancreatitis is well known. However, TMA leading to pancreatitis is more common than the latter. TMA and renal failure are both poor prognostic markers in acute pancreatitis. TMA, if not managed timely, can lead to severe morbidity and mortality. We report a case of a young boy in whom decisive and timely diagnosis and management of TMA post pancreatitis helped in complete patient and renal recovery.

A Friend or a Foe? Bariatric Surgery in Chronic Kidney Disease: A Case Report.

There has been a parallel rise in the need for bariatric surgery as the prevalence of obesity has increased by leaps and bounds over the last 2 decades. Certain procedures like Roux-en-Y gastric bypass are associated with nephrolithiasis, hyperoxaluria, and, rarely, oxalate nephropathy. We report an interesting case of a patient who had relentless progression of his kidney disease post-bariatric surgery.

Poorly Differentiated Lung Cancer with Intracardiac Extension Causing Malignant Stroke in a Peritoneal Dialysis Patient: a Case Report.

Cardiac involvement occurs in an almost one quarter of all the patients with lung cancer. Lymphatogenous spread is a more common route of tumor dissemination than the hematogenous spread. It was a retrospective case report. We hereby report a case of myocardial involvement by non-small cell lung cancer leading to an uncommon presentation of a malignant stroke and death in a peritoneal dialysis patient.

Solitary Fibrous Tumor of the Adrenal Gland.

OBJECTIVES: Solitary fibrous tumor (SFT) is a mesenchymal neoplasm that can arise at various anatomic locations. It is characterized by inv12(q13q13)-derived NAB2::STAT6 fusion, resulting in the nuclear expression of STAT6. Primary SFT of the adrenal gland is rare. We launched a multi-institutional collaboration to comprehend the overarching demographics, clinical and follow-up, macroscopic, microscopic, IHC, and FISH features of 9 patients with SFT of the adrenal gland. METHODS: We added a series of 9 patients to the collection of adrenal SFTs where the clinicopathologic parameters, including clinical presentation, imaging, histopathology, IHC, molecular profiles, and management and follow-up data, were analyzed comprehensively. A modified 4-variable risk stratification model, including age, tumor size, and necrosis, was applied. RESULTS: Our series consisted of 6 male and 3 female patients, ranging in age from 19 to 64 years (mean, 49.3 years). Abdominal pain (4) and fever with abdominal pain (1) were the presenting symptoms in 5 patients. In the remaining 4 patients, the tumors were detected by abdominal imaging for hypertension and diabetes. The size of the tumor ranged from 2 cm to 10.5 cm in maximum dimension. All tumors exhibited the morphology of a spindle cell SFT with a patternless architecture; 3 had a focal storiform arrangement. STAT6 positivity was observed in all tumors, and 7 were positive for CD34. Surgical resection was the primary modality of treatment. No adjuvant therapy was administered. Follow-up ranging from 7 months to 23 months was available for 7 patients. All were alive without disease recurrence or metastasis. Risk stratification placed 8 (88.9%) patients into a low-risk category and 1 into an intermediate-risk category. CONCLUSIONS: This series is the largest of adrenal SFTs to date. These tumors of the adrenal gland are predominantly spindle cell neoplasms with indolent behavior, with a wide age distribution and a slight male preponderance. Combining our cohort with the previously published cases, the majority of tumors fall into the low-risk category for the propensity to develop metastases. Owing to the rarity and age distribution associated with these tumors, the differential diagnosis is wide and requires a systematic approach for ruling out key differential diagnoses aided by STAT6 IHC.

Xanthogranulomatous Endometritis: A Benign Uncommon Masquerader of Malignancy.

Xanthogranulomatous endometritis is an uncommon benign lesion characterized by the destruction of endometrium and replacement by the sheets of foamy histiocytes, lymphocytes, plasma cells, multinucleated giant cells, fibrosis, calcification, and accompanying polymorphonuclear leukocytes. It is commonly mistaken for malignancy clinicoradiologically, and therefore, histopathological examination is of utmost importance. We report the case of a 61-year-old postmenopausal female who presented with pyometra, bulky uterus, and cervical stenosis, and histopathology revealed XGE.

Tumor Budding and Worse Pattern of Invasion Can Predict Nodal Metastasis in Oral Cancers and Associated With Poor Survival in Early-Stage Tumors.

The management and prognosis of oral squamous cell carcinoma (OSCC) depend on tumor stage and lymph node (LN) metastasis status. Early-stage (T1/T2 N0M0) OSCC comprises a heterogeneous group. We evaluated the role of histological parameters including worst pattern of invasion (WPOI) and tumor budding to determine the risk of LN metastasis in cases of OSCC and to determine the risk of recurrence and death in early-stage OSCC in north Indian patients. All cases of buccal mucosa and tongue SCC which underwent excision over 4 and half years were reviewed for histological parameters including histologic grade, WPOI, tumor budding, lymphovascular emboli (LVE), perineural invasion (PNI), depth of invasion (DOI), host lymphocyte response, and stromal response and compared to LN metastasis. Clinical follow-up of early-stage tumor was obtained and compared. A total of 126 cases of OSCC were included, of which 48 showed LN metastasis. Histological grade, WPOI, tumor budding (≥3/×40 field), LVE, and PNI were significantly associated with risk of LN metastasis. On multivariate analysis, WPOI and tumor budding were 2 most significant factors. Among the early-stage tumors with available follow up (n = 48), DOI, WPOI, tumor budding, and LVE were associated with a shorter overall survival, although it was not statistically significant. To conclude, WPOI and tumor budding are important risk factors for predicting LN metastasis in all stages of OSCC and associated with a poorer outcome in early-stage tumors. These are easy and reliable prognostic factors and should be included in the histopathological reporting guidelines.