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Background Leptomeningeal failure (LMF) represents a devastating progression of disease following resection of brain metastases (BrM). We sought to identify a biomarker at time of BrM resection that predicts for LMF using mass spectrometry-based proteomic analysis of resected BrM and to translate this finding with histochemical assays. Methods We retrospectively reviewed 39 patients with proteomic data available from resected BrM. We performed an unsupervised analysis with false discovery rate adjustment (FDR) to compare proteomic signature of BrM from patients that developed LMF versus those that did not. Based on proteomic analysis, we applied trichrome stain to a total of 55 patients who specifically underwent resection and adjuvant radiosurgery. We used competing risks regression to assess predictors of LMF. Results Of 39 patients with proteomic data, FDR revealed type I collagen-alpha-1 (COL1A1, P = .045) was associated with LMF. The degree of trichrome stain in each block correlated with COL1A1 expression (β = 1.849, P = .001). In a cohort of 55 patients, a higher degree of trichrome staining was associated with an increased hazard of LMF in resected BrM (Hazard Ratio 1.58, 95% CI 1.11–2.26, P = .01). Conclusion The degree of trichrome staining correlated with COL1A1 and portended a higher risk of LMF in patients with resected brain metastases treated with adjuvant radiosurgery. Collagen deposition and degree of fibrosis may be able to serve as a biomarker for LMF.

Introduction Perivascular epithelioid cell tumors (PEComas) are defined by the World Health Organization (WHO) as mesenchymal tumors arising from perivascular epithelioid cells with myomelanocytic immunophenotype. In the kidney, they are often referred to as epithelioid angimyolipoma (AML). Most are benign but some can be malignant. Their rarity and wide differential render diagnosis challenging. Case Presentation A 56-year-old male presented with a 3-month history of flank pain. Computed tomography (CT) identified bilateral necrotic heterogeneous enhancing kidney masses, with right significantly larger than left. Initially, the patient underwent a right radical nephrectomy. On gross examination, no tumor infiltration was observed. Histology demonstrated sheets of highly atypical cells with clear cytoplasm and easily identifiable nucleoli. Areas of spindle and rhabdoid differentiation were present. The initial diagnosis was renal clear cell (RCC) carcinoma, Fuhrman grade 4, with extensive rhabdoid and focal sarcomatoid features. A follow-up CT demonstrated a hypodense area within the right hepatic lobe. Status post liver resection and histomorphological examination, the lesion was identical to the renal mass except for focal areas of prominent epithelioid cells with eosinophilic cytoplasm. Immunohistochemical (IHC) stains of both masses were positive for Melan-A, HMB-45, and EMA but negative for PAX8, SOX10, S100, SMA, desmin, and cytokeratin. The initial diagnosis was amended to malignant AML with hepatic metastasis. Discussion and Conclusion Renal PEComa (epithelioid AML) is a rare tumor with a prevalence of 0.44%. While most are benign, some are malignant with metastatic potential. The differential diagnosis for PEComa is broad and includes more common tumors like RCC, melanoma, clear cell sarcoma, and liposarcoma. The presence of spindle and epithelioid histology with eosinophilic cytoplasm in RCC should prompt additional IHC workup (HMB45, Melan-A, SMA, and EMA) in order to exclude PEComa/AML.

Objectives: MDM2 gene amplification is associated with well-differentiated (WDL) and dedifferentiated liposarcomas (DDL). Using fluorescent in situ hybridization (FISH), we sought to characterize various patterns of MDM2 amplification among the morphologic spectrum of liposarcoma. Methods: Forty-six cases of liposarcoma in various sites were examined and included 22 WDLs, 14 DLLs, and 10 negative control subjects. Results: The MDM2 amplification ratio (MDM2/CEP12) was lower in WDL (10.2) compared with DDL (18.3) cases (P = .0000002). An amplification ratio of 16 showed optimal sensitivity (0.86) and specificity (0.96) as a cutoff point for progression to DDL. Borderline areas, defined as tumors with increased cellularity and atypia but with preserved lipomatous differentiation, showed a significantly higher MDM2 ratio (17.5; P = .0007) compared with WDL. Central (retroperitoneal and intra-abdominal) tumors also showed a significantly higher MDM2 ratio than peripheral ones (P = .02). Conclusions: Differences in MDM2 amplification profiles among liposarcomas could help further define and predict progression to high-grade neoplasia.

Objectives: Ocular specimens are relatively less common among all surgical specimens, and among them, orbital mesenchymal tumors are even less studied. Our goal is to study the prevalence and distribution of orbital mesenchymal tumor in our geographic area. Methods: We retrospectively reviewed the pathology archives for all orbital specimens between …

We performed a retrospective study to investigate the usefulness of immunohistochemical stains for the diagnosis of Helicobacter pylori (HP). We reviewed 200 consecutive gastric biopsy specimens, as well as immunohistochemical stains for HP. Of the biopsy specimens, 32 were positive for HP by immunohistochemical staining; of those, HP was seen on HE stains in 29 cases (91%). The number of high-power fields required to detect HP on HE-stained slides ranged from 1 to 25 (mean, 5.75). Combined significant (2+ or 3+) acute and chronic inflammation had a specificity of 98% and a negative predictive value of 97%. Our results show that, in our institution, HP can be seen relatively easily with HE staining in the majority of cases; however, a small number of cases with significant inflammation can be missed if stains are not used.

The most frequent malignant intracranial neoplasms are secondary ones, particularly carcinomas. Sarcomas are malignant mesenchymal neoplasms with relatively rare involvement of the brain. We reviewed our own institutional experience of metastatic sarcoma …

Extraskeletal small cell osteosarcoma is a rare soft-tissue tumor with production of osteoid by cytologically malignant small cells. Only six cases have been reported in the literature, two of which have cytologic description. We report a case of a 78-year-old man with a left axillary mass. …

Celiac disease (CD) and eosinophilic esophagitis (EOE) are two distinct disease entities affecting the gastrointestinal tract of pediatric patients. Recently it has been suggested that eosinophilic esophagitis is more prevalent in patients with celiac disease than the general population. We studied the association between these two disease entities in our pediatric population. We reviewed our …