DNA methylation profiling of meningiomas highlights clinically distinct molecular subgroups.

BACKGROUND: Introduction of the classification of brain tumours based on DNA methylation profile has significantly changed the diagnostic approach. Due to the paucity of data on the molecular profiling of meningiomas and their clinical implications, no effective therapies and new treatments have been implemented. METHODS: DNA methylation profiling, copy number analysis, targeted sequencing and H3K27me3 expression was performed on 35 meningiomas and 5 controls. RESULTS: Unsupervised hierarchical clustering (UHC) analysis revealed four distinct molecular subgroups: Malignant; Intermediate; Benign A, and Benign B. Molecular heterogeneity was observed within the same grade as the Intermediate, Benign A, and Benign B subgroups were composed of WHO grade 1 as well as grade 2 cases. There was association of mutations with distinct methylation subgroups (NF2, AKT1, SMO, TRAF7 and pTERT). Loss of chromosome 22q was observed across all subgroups. 1p/14q co-deletion was seen in 50% of malignant and intermediate while CDKN2A loss was predominantly observed in malignant subgroup (50%). Majority of malignant (75%) and a small proportion of other subgroups (Intermediate: 25%, Benign A: 38.5%, and Benign B: 20%) harboured H3K27me3 loss. 38,734 genes were dysregulated amongst the four subgroups. DKFZ classified 71% cases with acceptable score. On survival analysis, methylation profiling had significant impact on progression-free-survival in WHO grade1 and 2 meningiomas (p = 0.0051). CONCLUSION: Genome-wide DNA methylation profiling highlights clinically distinct molecular subgroups and heterogeneity within the same grade of meningiomas. Molecular profiling can usher in a paradigm shift in meningioma classification, prognostic prediction, and treatment strategy.

The evolution of pleomorphic xanthoastrocytoma: from genesis to molecular alterations and mimics.

Pleomorphic xanthoastrocytomas (PXAs) are rare tumors accounting for less than 1% of astrocytomas. They commonly occur in young patients and have relatively favorable prognosis. However, they are well known to have heterogenous morphology and biological behavior with the potential to recur and disseminate throughout the central nervous system, especially their anaplastic counterparts. Recent advances in the molecular characterization have discovered BRAFp.V600E mutations in conjunction with CDKN2A/B deletions and TERTp mutations to be the most frequent alterations in PXAs. These tumors can present a diagnostic challenge as they share overlapping histopathological, genomic as well as methylation profile with various other tumor types, particularly epithelioid glioblastomas (eGBs). This review provides the spectrum of evolution of PXAs from their genesis to recent molecular insights and attempts to review pathogenesis and relationship to other tumors that they mimic especially eGB. It is postulated based on evidence from literature that PXA and eGB are possibly related and not distinct entities, being two ends of a continuous spectrum of malignant progression (grade 2-grade 4) with anaplastic PXA (grade 3) lying in between. Future WHO classifications will have to possibly redefine these tumors using more confirmatory data from larger studies.

Role of CDKN2A deletion in grade 2/3 IDH-mutant astrocytomas: need for selective approach in resource-constrained settings.

OBJECTIVE: The authors aimed to assess the frequency of homozygous CDKN2A deletion in isocitrate dehydrogenase (IDH)-mutant diffuse astrocytomas (grade 2/3) and to narrow down the clinicopathological indications in which the CDKN2A fluorescence in situ hybridization (FISH) assay is cost-effective in resource-constrained settings. METHODS: IDH-mutant astrocytomas were analyzed for ATRX, p53, MIB1-LI, and p16 expression using immunohistochemistry. The FISH assay was used to evaluate CDKN2A deletion and 1p/19q codeletion. Survival outcomes were assessed according to the different molecular markers. RESULTS: A total of 150 adult patients with IDH-mutant grade 2 (n = 95) and grade 3 (n = 55) astrocytomas (145 primary and 5 recurrent) were analyzed. Using a cutoff value of 30% for defining significant homozygous CDKN2A deletion, none of the grade 2 and 10.9% (6/55) of grade 3 astrocytomas showed this deletion (4 primary and 2 recurrent grade 3 tumors) and were reclassified as grade 4. This mutation was more frequent in recurrent (40%, 2/5) than primary (2.76%, 4/145) gliomas. Half (3/6, 50%) of the CDKN2A-deleted cases demonstrated poor outcomes; 2 of these cases experienced recurrence at 12 and 36 months after surgery, and 1 died at 5 months. The majority of CDKN2A-deleted cases showed marked cellularity (100%), pleomorphism (100%), brisk mitosis (83.3%), and tumor giant cell formation (83.4%). None of the cases with retained p16 expression harbored this deletion. Both overall survival (p = 0.039) and progression-free survival (p = 0.0045) were found to be worse in cases with p16 loss. Selectively performing CDKN2A FISH only in high-risk cases with histomorphological features of anaplasia, p16 loss, or recurrent tumors achieved a sensitivity and negative predictive value of 100%. This approach would have resulted in saving 41.1% of the original expenditure ($6900 US per 150 samples) and 27.6 person-minutes per sample without compromising the identification of deleted cases. CONCLUSIONS: Homozygous CDKN2A deletion is conspicuously absent in grade 2 and rare in primary grade 3 IDH-mutant astrocytomas. The authors propose that restricting use of the FISH assay to cases showing histomorphological features of anaplasia, p16 loss, or recurrent tumors will help this platform to be utilized in the most cost-effective manner in resource-constrained settings.

Retrospective analysis of IgG4-related disease cases at a tertiary care centre in India.

Objectives: IgG4-related disease (IgG4-RD) is a chronic inflammatory disorder with prominent fibrosis. This retrospective analysis was undertaken to study the clinical, laboratory, and radiological characteristics of patients with extra-pancreatic IgG4-RD and their response to treatment at a tertiary care centre located in northern India. Material and methods: Patient data from our centre between January 2017 and January 2021 were reviewed. Probable/definite IgG4-RD cases were included in the analysis. Results: A total of 14 cases were identified with a median age of 39 years (range 19-56 years). There were 10 males and 4 females. All patients presented with slowly progressive soft tissue swellings with pain/discomfort related to local mass effect. The median delay in diagnosis was 9.5 months (range 2-72 months). Cross-sectional imaging showed soft tissue masses in all cases. All contrast-enhanced studies (n = 7) showed enhancement on computed tomography and magnetic resonance imaging scan. F-18 fluorodeoxyglucose-avidity was observed in 8 of 9 (88.9%) cases. Biopsies performed in 12 of these were classified as definite in 8 and possible IgG4-RD in 4 cases. Patients were treated with a median dose of 1 mg/kg/day (range 0.5-1 mg/kg/day) prednisolone. Steroids were successfully tapered in all 12 cases with 41.6% (5 of 12) being off corticosteroids at a median follow-up of 10 months (range 0-18 months). Two patients were lost to follow-up. Conclusions: IgG4-related disease is a chronic illness with a wide spectrum of manifestations, in which the diagnosis is often delayed, but it shows an excellent response to treatment. Efforts must be made to increase awareness among physicians about this disease to institute appropriate treatment as early as possible.

Ependymosarcoma harboring C11orf95:RELA fusion transcript: Report of two cases and review of the literature.

Ependymoma is a relatively rare glial tumor of the central nervous system that arise from the cells lining the ventricles and central canal of the spinal cord. Ependymosarcoma (ES) is a newly introduced tumor entity of uncertain prognosis characterized by a rare phenomenon of a malignant mesenchymal transition arising within an ependymoma. ESs are surgically challenging tumors for diagnosis and therapy with a high incidence of morbidity and mortality. Here, we report two diagnostically challenging cases of primary ES in a 25-year-old female and a 17-year-old male. Both the cases presented with progressive and sequential neurological deficits over a period of five to eight months, and histological examination revealed a biphasic gliomesenchymal architecture comprised of anaplastic ependymomatous and sarcomatous components. Molecular genetic analysis revealed the presence of type 1 C11orf95:RELA fusion transcript. To date, 22 cases of ES have been reported in the literature, and only one case harbored type 1 C11orf95:RELA fusion transcript.

SLIC-supervoxels-based response evaluation of osteosarcoma treated with neoadjuvant chemotherapy using multi-parametric MR imaging.

OBJECTIVE: Histopathological examination (HPE) is the current gold standard for assessing chemotherapy response to tumor, but it is possible only after surgery. The purpose of the study was to develop a noninvasive, imaging-based robust method to delineate, visualize, and quantify the proportions of necrosis and viable tissue present within the tumor along with peritumoral edema before and after neoadjuvant chemotherapy (NACT) and to evaluate treatment response with correlation to HPE necrosis after surgery. METHODS: The MRI dataset of 30 patients (N = 30; male:female = 24:6; age = 17.6 ± 2.7 years) with osteosarcoma was acquired using 1.5 T Philips Achieva MRI scanner before (baseline) and after 3 cycles of NACT (follow-up). After NACT, all patients underwent surgical resection followed by HPE. Simple linear iterative clustering supervoxels and Otsu multithresholding were combined to develop the proposed method-SLICs+MTh-to subsegment and quantify viable and nonviable regions within tumor using multiparametric MRI. Manually drawn ground-truth ROIs and SLICs+MTh-based segmentation of tumor, edema, and necrosis were compared using Jacquard index (JI), Dice coefficient (DC), precision (P), and recall (R). Postcontrast T1W images (PC-T1W) were used to validate the SLICs+MTh-based necrosis. SLICs+MTh-based necrosis volume at follow-up was compared with HPE necrosis using paired t test (p ≤ 0.05). RESULTS: Active tumor, necrosis, and edema were segmented with moderate to satisfactory accuracy (JI = 62-78%; DC = 72-87%; P = 67-87%; R = 63-88%). Qualitatively and quantitatively (DC = 74 ± 9%), the SLICs+MTh-based necrosis area correlated well with the hypointense necrosis areas in PC-T1W. No significant difference (paired t test, p = 0.26; Bland-Altman plot, bias = 2.47) between SLICs+MTh-based necrosis at follow-up and HPE necrosis was observed. CONCLUSION: The proposed multiparametric MRI-based SLICs+MTh method performs noninvasive assessment of NACT response in osteosarcoma that may improve cancer treatment monitoring, planning, and overall prognosis. KEY POINTS: • The simple linear iterative clustering supervoxels and Otsu multithresholding-based technique (SLICs+MTh) successfully estimates the proportion of necrosis, viable tumor, and edema in osteosarcoma in the course of chemotherapy. • The proposed technique is noninvasive and uses multiparametric MRI to measure necrosis as an indication of anticancer treatment response. • SLICs+MTh-based necrosis was in satisfactory agreement with histological necrosis after surgery.

Multimodal Management of Congenital Orbital Malignant Rhabdoid Tumor: Review of Literature and Report of a Rare Case.

BACKGROUND: Malignant rhabdoid tumor (MRT) is a rare and aggressive tumor with a dismal prognosis. It commonly arises in the brain (65%), soft tissues (26%), and the kidney (9%). Primary orbital involvement is extremely rare. Although it has been mostly described in children below 2 years old, presentation at birth is sparsely reported. OBSERVATION: We have described a case of congenital orbital MRT, who presented with rapidly progressive right-sided proptosis and was initially treated with subtotal resection and postoperative chemotherapy with ICE (Ifosfamide, Carboplatin, Etoposide) regimen. On local progression the child was treated with palliative radiotherapy (20 Gy) to the right orbit and second-line chemotherapy with VAC (Vincristine, Adriamycin, Cyclophosphamide) regimen. Unfortunately he died due to progressive disease 4 months after the initial diagnosis. CONCLUSIONS: This report highlights the importance of awareness of orbital MRT as a differential diagnosis of rapidly progressing proptosis in the neonatal period. This tumor is often refractory to conventional multimodality treatment and more intensive and innovative treatment approaches are clearly needed in future.

Sinonasal amelanotic melanoma with neuroendocrine differentiation: a diagnostic conundrum.

Mucosal malignant melanoma of the head and neck (HN) is a rare and aggressive neoplasm which constitutes only 1% of all melanomas. Neuroendocrine differentiation is an extremely unusual phenomenon in mucosal melanomas, of which five cases have been reported. We report a rare case of a 63-year-old female who developed sinonasal amelanotic melanoma with immunohistochemical expression of neuroendocrine markers, presenting a diagnostic dilemma. Ultrastructural evidence of melanosomes and neurosecretory granules aided in arriving at the diagnosis. Aberrant immunoexpression of neuroendocrine markers, particularly in an amelanotic melanoma, has critical diagnostic implications, as various malignancies with undifferentiated histomorphology occur at this site, many of which stain positively with neuroendocrine markers. We discuss the differential diagnoses and recommend a high index of suspicion so as not to miss the diagnosis of mucosal melanoma at this location.

mTOR pathway activation in focal cortical dysplasia.

BACKGROUND: Focal cortical dysplasia (FCD) is a localized cortical malformation and considerable morphological overlap exists between FCD IIB and neurological lesions associated with Tuberous sclerosis complex (TSC). Abnormal mTOR pathway secondary to somatic mTOR mutation and TSC gene mutation linked to PI3K/AKT/mTOR pathway have supported the hypothesis of common pathogenesis involved. Role of converging pathway, viz. Wnt/ß-Catenin and mTOR is unknown in FCD. We aimed to analyse FCD IIB for TSC1/TSC2 mutations, immunoreactivity of hamartin, tuberin, mTOR and Wnt signalling cascades, and stem cell markers. MATERIALS AND METHODS: Sixteen FCD IIB cases were retrieved along with 16 FCD IIA cases for comparison. Immunohistochemistry was performed for tuberin, hamartin, mTOR pathway markers, markers of stem cell phenotype, and Wnt pathway markers. Mutation analysis for TSC1 and TSC2 was performed by sequencing in 9 FCD cases. RESULTS: All FCD cases showed preserved hamartin and tuberin immunoreactivity. Aberrant immunoreactivity of phospho-P70S6 kinase, S6 ribosomal, phospho-S6 ribosomal and Stat3 was noted in FCD IIB, with variable phospho-4E-BP1 (45%) and absent phospho-Stat3 expression. Immunoreactivity for phospho-P70S6 kinase (100%), S6 ribosomal protein (100%) and Stat3 (100%) was noted in FCD IIA, but not for phospho-S6 ribosomal, phospho-4E-BP1 and phospho-Stat3. c-Myc immunoreactivity was noted in all FCD cases. Nestin (81%) and Sox 2 (88%) stained balloon cells in FCD IIB (44%), while in FCD IIA cases were negative. All FCD cases were immunopositive for Wnt, but were negative for ß-Catenin and cyclin-D1. TSC mutations were detected in two cases of FCD IIB. CONCLUSION: Abnormal mTOR pathway activation exists in FCD IIB and IIA, however, shows differential immunoreactivity profile, indicating varying degrees of dysregulation. Labelling of neuronal stem cell markers in balloon cells suggests they are phenotypically immature. TSC1/2 mutation play role in the pathogenesis of FCD. Deep targeted sequencing is preferred diagnostic technique since conventional sanger sequencing often fails to detect low-allele frequency variants involved in mTOR/TSC pathway genes, commonly found in FCD.

Primary intracranial malignant ectomesenchymoma in an adult: Report of a rare case and review of the literature.

Malignant ectomesenchymoma (MEM) is an exceedingly rare rapidly progressing tumor of soft tissues of the central nervous system, believed to be derived from neural crest cells. The majority of cases have been observed in young children or adolescents. So far only 11 patients with intracranial manifestations (with confirmed clinicopathological data) have been documented. We report the first case of adult intracranial MEM in a 54-year-old man who presented with a 4 months history of headache and weakness of right side of the body. Magnetic resonance imaging showed a homogenously enhanced dural-based lesion in the left fronto-temporo-parietal lobe with significant perilesional edema and mass effect. No metastatic disease was identified and the lesion was grossly resected. Histopathological and immunohistochemical examination revealed mature and immature neurons and bizarre astrocytes admixed with a mesenchymal spindle cell (rhabdomyoblastic) component. Specific risk factors that contribute toward the development of MEM are unknown. Due to the scarcity of reported cases the role of adjuvant therapy is unclear.

Analysis of PD-L1 expression and T cell infiltration in different molecular subgroups of diffuse midline gliomas.

Diffuse midline gliomas (DMGs) are rare and devastating tumors with limited therapeutic options. Programmed death-ligand 1 (PD-L1) expression represents a potential predictive biomarker for immunotherapy. One hundred and twenty-six DMGs (89 adult and 37 pediatric) were assessed for immune profile (PD-L1, cluster of differentiation (CD3, CD8) and genetic markers (mutation in 27th amino acid of histone H3 (H3K27M), alpha thalassemia/mental retardation syndrome X-linked (ATRX), isocitrate dehydrogenase 1 (IDH1), p53) by immunohistochemistry. Sanger sequencing was done for IDH1 and H3K27M. The thalamus was the commonest site. Four molecular subgroups of DMGs were identified. H3K27M mutation was more frequent in children (P = 0.0001). The difference in median overall survival (OS) was not significant in any of the four molecular subgroups (P > 0.05). PD-L1 expression was significantly higher in H3K27M/IDH1 double-negative adult glioblastomas (GBMs) (P = 0.002). Strong PD-L1 expression was more frequent in grade IV tumors and thalamic location, although the difference was not significant (P = 0.14 and P = 0.19 respectively). Positive PD-L1 expression was significantly associated with high tumor-infiltrating lymphocytes count (P < 0.05). There was no significant difference in median OS in PD-L1-positive versus negative cases among four genetic subgroups (P > 0.05). On univariate analysis, there was no direct correlation of PD-L1 with any genetic alteration, except H3K27M mutation (P = 0.01). CD3 infiltration was similar in both adults and pediatric ages (84.3% and 78.4%, respectively) while CD8 expression was significantly greater in adults compared to children (74.1% vs 37.8%, P = 0.0001). This is the first comprehensive analysis highlighting molecular and immune profiles of DMGs. Despite molecular and clinicopathological diversity, overall survival in DMGs remains dismal. Multicentric studies with larger numbers of cases should be undertaken for stratifying DMGs according to their age, immune and molecular profiles, to develop effective immunotherapies.

Clinicopathological and molecular characteristics of pediatric meningiomas.

Molecular and clinical characteristics of pediatric meningiomas are poorly defined. Therefore, we analyzed clinical, morphological and molecular profiles of pediatric meningiomas. Forty pediatric meningiomas from January 2002 to June 2015 were studied. 1p36, 14q32 and 22q-deletion were assessed by fluorescent in situ hybridization and mutations of most relevant exons of AKT, SMO, KLF4, TRAF and pTERT using sequencing. Expression of GAB1, stathmin, progesterone receptor (PR), p53 along with MIB-1 LI was examined using immunohistochemistry. There were 36 sporadic and four NF2 associated meningiomas. Among sporadic meningiomas, the majority (72.2%) of cases harbored 22q-deletion. Difference in frequency of combined 1p/14q deletion in Grade-I versus Grade-II/III tumors was not significant (13.7% vs 28.5%, P = 0.57). PR immunoreactivity was seen in 65.5% of Grade-I and 14.2% of Grade-II/III tumors (P = 0.03). The majority (97.2%) of meningiomas were immunonegative for p53. Stathmin and GAB co-expression was observed in 58.3% of cases. Notably, AKT, SMO, KLF4, TRAF7 (exon 17) and pTERT mutations were seen in none of the cases analyzed. 1p/14q codeletion was frequent in skull base as compared to non-skull base meningiomas (23% vs 11.1%, P = 0.37). All NF2 meningiomas harbored 22q-deletion and showed GAB and stathmin co-expression while none showed 1p/14q loss. Pediatric meningiomas share certain phenotypic and cytogenetic characteristics with adult counterparts, but GAB and stathmin co-expression in the majority of cases and non-significant difference in frequency of 1p/14q co-deletion between low- and high-grade meningiomas indicate an inherently aggressive nature. Characteristic AKT/SMO, KLF4/TRAF7 and pTERT genetic alterations seen in adults are distinctly absent in pediatric meningiomas.

Pompe disease: An Indian series diagnosed on muscle biopsy by ultrastructural characterization.

Pompe disease (PD) is a lysosomal storage disorder characterized by glycogen accumulation in muscle, with infantile-onset (IOPD) and late-onset (LOPD) types. Nineteen cases of PD were diagnosed over a 14-year period on muscle biopsy by ultrastructural examination. Pools of glycogen (intralysosomal and cytoplasmic) and excessive phagocytosis were seen in myofibers on electron microscopy. Glycogen was noted in endothelial cells in IOPD. Although PD accounts for a small fraction of muscle diseases, timely accurate diagnosis is imperative as it is treatable. Ultrastructural examination is necessary to confirm the diagnosis in cases with non-diagnostic light microscopic features, especially in adult LOPD patients.

Biphenotypic sinonasal sarcoma: A series of six cases with evaluation of role of ß-catenin immunohistochemistry in differential diagnosis.

INTRODUCTION: Biphenotypic sinonasal sarcoma (BSNS) is a recently described mesenchymal tumor exclusive to the sinonasal region. It is a low grade sarcoma, displaying evidence of myogenic and neural differentiation. Role of ß-catenin immunohistochemistry in distinguishing it from its morphological mimics is not well-established. We conducted this study to identify cases of BSNS from our archives, and to examine immunopositivity for ß-catenin in them as well as in its close differential diagnosis. METHODS: All cases of nasal cavity and paranasal sinus mesenchymal neoplasms were identified. Histopathological features were reviewed. Cases showing smooth muscle actin (SMA) and S-100 immunopositivity, and typical morphology were reclassified as BSNS. ß-catenin immunoexpression was assessed. RESULTS: Twenty-one mesenchymal tumors, including 12 sinonasal hemangiopericytoma (SNHPC), five solitary fibrous tumors (SFT), three BSNS, and one synovial sarcoma were identified. Three SNHPC cases were reclassified as BSNS. BSNS patients included one male and five females, with mean age of 51years. Five BSNS cases (83.3%) showed nuclear ß-catenin immunopositivity. SNHPC cases also were ß-catenin positive (60%). CONCLUSION: BSNS is a rare sinonasal neoplasm, frequently misdiagnosed as SNHPC and SFT. ß-catenin immunopositivity is seen in majority of cases, indicating a role in pathogenesis. However, due to positivity in other tumors like SNHPC, it has limited role in differential diagnosis.

Is spindle cell oncocytoma a true entity or a variant of pituicytoma? A case report with review of literature.

Spindle cell oncocytoma (SCO) is a newly described rare entity simulating clinicoradiological features of a nonfunctional pituitary adenoma and is corresponding to the category of World Health Organization grade I tumor. However, because of the reported incidence of recurrence and invasive presentation in some cases, its categorization as a low grade tumor is questionable. Earlier, it was thought to arise from the folliculostellate cells of adenohypophysis. Recently, few reports have described expression of thyroid transcription factor-1 [TTF-1], which is a specific marker for pituicytes of neurohypophysis, suggesting this tumor to be a variant of pituicytoma. We describe a case of SCO in a 28-year-old young female patient with TTF-1 immunopositivity, and ultra-structurally showing abundant mitochondria along with few neurosecretory granules.

Childhood macrophagic myofasciitis: A series from the Indian subcontinent.

INTRODUCTION: Macrophagic myofasciitis (MMF) is a rare disorder, reported mainly in European adults, with occasional childhood cases. We report a series of 6 patients with pediatric MMF from the Indian subcontinent. METHODS: Clinical details, creatine kinase levels, and results of electromyography are described for patients diagnosed with MMF. Fresh-frozen and formalin-fixed muscle biopsies were evaluated by hematoxylin-eosin staining, histochemistry, immunohistochemistry, and electron microscopy. RESULTS: Six of 2,218 muscle biopsies were diagnosed as MMF; patient charts were reviewed. The 6 patients were all children; all presented with hypotonia and/or motor delay. Mean age at diagnosis was 16.2 months. There were 4 boys and 2 girls. All had a history of hepatitis B vaccination. Histopathology revealed infiltration by sheets of large periodic acid-Schiff stain-positive histiocytes. Ultrastructural examination demonstrated needle-shaped crystals within histiocytes. One patient had a co-existent neuromuscular disorder, merosin-deficient congenital muscular dystrophy. CONCLUSIONS: MMF is a rare inflammatory myopathy that should be considered in the differential diagnosis of congenital myopathies in children. Muscle Nerve 56: 71-77, 2017.

p40 & thyroid transcription factor-1 immunohistochemistry: A useful panel to characterize non-small cell lung carcinoma-not otherwise specified (NSCLC-NOS) category.

BACKGROUND & OBJECTIVES: Accurate histopathological subtyping of non-small cell lung carcinoma (NSCLC) is essential for targeted therapeutic agents. Immunohistochemistry (IHC) is helpful in identification of different tumour subtypes. In this study two marker approaches, one each for glandular and squamous cell differentiation was applied to maximize the proportion of accurately subtyped NSCLC not otherwise specified (NOS) tumours on small biopsy samples. METHODS: Two hundred and sixty three consecutive lung biopsies of primary lung carcinoma were prospectively studied. These were subtyped first morphologically and then by IHC for p40 and thyroid transcription factor-1 (TTF-1). The diagnosis of NSCLC-NOS before and after addition of IHC was evaluated. Results were correlated and validated with morphologically proven cases and matched surgical specimens. RESULTS: Based on morphology, only 140 of the 263 (53.2%) cases of NSCLC were characterized, whereas 123 (46.7%) were classified as NSCLC-NOS type. With addition of IHC (p40 and TTF-1), the latter category reduced to 14.4 per cent and a sum of 225 (85.5%) cases were accurately subtyped into squamous cell carcinoma, adenocarcinoma and adenosquamous carcinoma. p40 showed 100 per cent sensitivity and specificity for squamous differentiation whereas TTF-1 showed sensitivity of 85.3 per cent and specificity of 98.1 per cent. Ninety per cent correlation of morphologic subtypes was achieved with matched resected specimens. INTERPRETATION & CONCLUSIONS: Our results showed that an approach of using only a two-antibody panel (p40 and TTF-1) might help in reduction of diagnostic category of NSCLC-NOS significantly and contribute in saving tissue for future molecular testing.

Melanosomal melanin pigment in pleomorphic xanthoastrocytoma, evidence for neuronal-glial origin: A case report with review of the literature.

We describe a unique case of pleomorphic xanthoastrocytoma (PXA) in a 19-year-old male presenting with the chief complaint of seizures. On radiology, the tumor was located in the temporal lobe. It was cortically based and solid cystic in nature. Light microscopy showed pleomorphic large polygonal cells with inclusions, nuclear clustering, lipidization, and foamy cytoplasm intermingled with spindle cells arranged in sweeping pattern and focally containing cytoplasmic brownish black pigment. The pigment stained black with Fontana-Masson stain and bleached with potassium permanganate. Gomori silver stain showed reticulin fibers surrounding individual tumor cells as well as groups of cells. On immunohistochemistry, tumor cells were positive for GFAP, S-100 and focally for synaptophysin and CD34 but negative for HMB-45. CD34 revealed a specific membranous pattern around individual cells as well as groups of cells along the fibers replicating a reticulin pattern. The ultrastructural examination showed supporting melanosomes, thus confirming the melanin pigment. Sequencing for BRAF V600E showed a heterozygous mutation. To our knowledge only five cases of PXA with melanin pigment have been reported and none of which described BRAF V600E mutation analysis. This case provides further insight into the origin and pathogenesis of pigmented astrocytic tumor, additionally highlighting the characteristic CD34 staining pattern.

T cell lymphoblastic lymphoma/leukemia within an adrenocorticotropic hormone and thyroid stimulating hormone positive pituitary adenoma: A cytohistological correlation emphasizing importance of intra-operative squash smear.

We present a rare case of primary pituitary T cell lymphoma/leukemia (T-LBL) in association with adrenocorticotropic hormone (ACTH) and thyroid stimulating hormone (TSH) expressing pituitary adenoma in a 55-year-old woman highlighting the importance of intra-operative squash smears examination. The patient presented with complaints of headache, diminution of vision and recent onset altered sensorium. MRI revealed a mass lesion in the sellar-suprasellar region with non-visualization of pituitary gland separately, extending to involve adjacent structures diagnosed as invasive pituitary macroadenoma. Intra-operative tissue was sent for squash smear examination. The cytology showed a tumor comprising of sheets of immature lymphoid cells intermixed with clusters of pituitary acinar cells with many mitoses and tingible body macrophages. A diagnosis of presence of immature lymphoid cells within the pituitary was offered and differentials of infiltration by lymphoma cells from systemic disease versus primary central nervous lymphoma-like lymphoma arising in the pituitary adenoma were considered. Later paraffin section examination and immunohistochemistry corroborated with the squash findings and a final diagnosis of primary pituitary T cell lymphoma/leukemia in association with ACTH and TSH expressing pituitary adenoma was made. To date, only six cases of primary pituitary T cell lymphomas, including three T-LBL cases, have been reported. This is the seventh case and first one additionally describing cytohistological correlation and importance of intra-operative cytology.

Progressive multifocal leukoencephalopathy in a 44-year old male with idiopathic CD4+ T-lymphocytopenia treated with mirtazapine and mefloquine.

Progressive multifocal leukoencephalopathy (PML) is an opportunistic viral infection of the central nervous system caused by the reactivation of John Cunningham virus (JCV) in immunocompromised patients, most commonly in human immunodeficiency virus (HIV) infection, and less commonly in those receiving various immunosuppressive regimens. Prognosis of untreated PML is grave and the mainstay of treatment is the reversal of immunosuppression, usually by institution of antiretroviral drugs in HIV patients and cessation of immunosuppressive therapies in others. PML is increasingly being reported in those with minimal or occult immunosuppression. A small fraction of these patients meet the criteria for idiopathic CD4+ T-lymphocytopenia (ICL) after exclusion of all secondary causes of lymphocytopenia, including HIV. A 44-year-old previously healthy male presented with clinical and radiological features suggestive of PML. Cerebrospinal fluid samples were repeatedly negative for JCV. Immunohistochemistry on brain biopsy eventually confirmed PML. Despite extensive work-up, the only abnormality detected was an unexplained and persistently low absolute CD4+ T-lymphocyte count. Based on the limited available literature on the treatment of non-HIV PML, he was treated with a combination of mirtazapine and mefloquine with clinical improvement. Non-HIV PML remains relatively uncommon, and PML as a presenting feature of ICL is rare. It is important to document and follow these patients to be able to assess the relative risks associated with various causes and formulate effective therapeutic strategies.