Biphasic papillary (biphasic squamoid alveolar) renal cell carcinoma: a clinicopathologic and molecular study of 17 renal cell carcinomas including 10 papillary adenomas.

Biphasic papillary renal cell carcinoma (synonymous with biphasic squamoid alveolar renal cell carcinoma) is considered within the spectrum of papillary renal cell carcinoma (PRCC). With < 70 reported cases of biphasic PRCC, there is limited data on the pathologic spectrum and clinical course. Seventeen biphasic PRCC cases and 10 papillary adenomas with similar biphasic morphology were assessed. The mean age of the biphasic PRCC patients was 62 years (male to female ratio of 1.8:1), from 10 partial nephrectomies, 6 radical nephrectomies, and 1 biopsy. The mean tumor size was 3.6 cm (range 1.6-8 cm), with 24% showing multifocality. Fifteen out of 17 cases were limited to the kidney (one of which was staged as pT2a but had lung metastases at diagnosis) and 2/17 cases were staged as T3a. All tumors showed typical biphasic morphology with an extent of squamoid foci widely variable from 10 to 95%. Emperipolesis was identified in 88% of cases. All biphasic PRCC tested exhibited positivity for PAX8 (16/16), keratin 7 (17/17), EMA (15/15), AMACR (17/17), and vimentin (12/12) in both large and small cells; cyclin D1 was only expressed in the large cells (16/16). The 10 papillary adenomas showed a similar immunoprofile to biphasic PRCC. NGS testing performed on 13 biphasic PRCC revealed 4 (31%) harboring MET SNVs. In 1/5 (20%) papillary adenomas, a pathogenic MET SNV was identified. Biphasic PRCC is rare with a generally similar immunoprofile to "type 1" PRCC but with notable strong positivity for cyclin D1 in the large cell component. Although most of the biphasic PRCC cases were of small size, low stage, and with an indolent behavior, one patient had metastatic disease and one patient died of the disease.

Scars Run Deep: Problematic Morphology and Immunoprofile of Scars in Renal Oncocytomas.

In some instances, the central scar of renal oncocytoma can demonstrate entrapped cells with unusual morphology and aberrant immunoprofile creating potential diagnostic confusion. Herein, 100 renal oncocytomas containing scars with embedded epithelial cells were identified from 6 institutions, including nephrectomies (64% partial, 36% radical) of similar laterality (left = 51%) and sex distribution (male = 56%), with patient ages ranging from 38 to 86 years (mean = 64.3years) and tumor sizes ranging from 2 to 16 cm (mean = 5.3 cm). Immunohistochemistry was performed on all tumors for KRT7, KIT, vimentin, and CA9 with staining intensity and extensity separately analyzed. Of 4 architectural patterns of cells within the scar, 60% showed tubular pattern. Of 4 cytologies within the scar, flat/elongated (49%) and cuboidal cells (40%) predominated. Within the scar, 62% showed eosinophilic cytoplasm, with 38% showing both cleared and eosinophilic cytoplasm; notably, 79% showed higher grade nuclei than typical oncocytes. A subset of scar cells showed mucinous-like basophilic secretions (19%). Compared to background renal oncocytoma, tumor cells within the scar were more often positive for vimentin, KRT7, and CA9 and more frequently negativity for KIT. Specifically, of the notable "aberrant" immunoprofiles, 79% showed KRT7 positivity/KIT negativity/vimentin positive, 84% showed vimentin positivity/CA9 positivity, and 78% showed KIT negativity/vimentin positivity/CA9 positivity. While encountering scars within renal oncocytomas is not uncommon, what is not well appreciated is the unique morphology and immunohistochemistry of tumor cells within the scar. Comparing tumor morphology and immunoprofile of the scar to the background oncocytoma is helpful to avoid interpretative confusion.

Metastatic solid tumors to the testis: a clinicopathologic evaluation of 157 cases from an international collaboration.

To elucidate the spectrum of metastatic solid tumors to the testis and their clinicopathologic features. The databases and files of 26 pathology departments from 9 countries on 3 continents were surveyed to identify metastatic solid tumors to the testis and to characterize their clinicopathologic features in detail. We compiled a series of 157 cases of metastatic solid tumors that secondarily involved the testis. The mean patient age at diagnosis was 64 years (range, 12-93 years). Most patients (127/144; 88%) had clinical manifestation of the disease, with testicular mass/nodule (89/127; 70%) being the most common finding. The main mechanism of testicular involvement was metastasis in 154/157 (98%) cases. Bilateral testicular involvement was present in 12/157 (8%) patients. Concurrent or prior extratesticular metastases were present in 78/101 (77%) patients. The diagnosis was made mainly in orchiectomy specimens (150/157; 95%). Different types of carcinomas (138/157; 87%), most commonly adenocarcinoma (72/157; 46%), were the most common malignancies. The most common primary carcinomas included prostatic (51/149; 34%), renal (29/149; 20%), and colorectal (13/149; 9%). Intratubular growth was identified in 13/124 (11%) cases and paratesticular involvement was found in 73/152 (48%) cases. In patients with available follow-up (110/157; 70%), more than half (58/110; 53%) died of disease. In this largest series compiled to date, we found that most secondary tumors of the testis represent metastases from the genitourinary and gastrointestinal tract carcinomas and typically occur in the setting of disseminated disease.

Metastatic solid tumours to the penis: a clinicopathologic evaluation of 109 cases from an international collaboration.

AIMS: To elucidate the spectrum of metastatic tumours to the penis and their clinicopathologic features. METHODS: The databases and files of 22 pathology departments from eight countries on three continents were queried to identify metastatic solid tumours of the penis and to characterize their clinical and pathologic features. RESULTS: We compiled a series of 109 cases of metastatic solid tumours that secondarily involved the penis. The mean patient age at diagnosis was 71 years (range, 7-94 years). Clinical presentation commonly included a penile nodule/mass (48/95; 51%) and localised pain (14/95; 15%). A prior history of malignancy was known in 92/104 (89%) patients. Diagnosis was made mainly on biopsy (82/109; 75%), or penectomy (21/109; 19%) specimens. The most common penile locations were the glans (45/98; 46%) and corpus cavernosum (39/98; 39%). The most frequent histologic type was adenocarcinoma (56%). Most primary carcinomas originated in the genitourinary (76/108; 70%) and gastrointestinal (20/108; 18%) tracts, including prostate (38/108; 35%), urinary bladder (27/108; 25%), and colon/rectum (18/108; 17%). Concurrent or prior extrapenile metastases were identified in 50/78 (64%) patients. Clinical follow-up (mean 22 months, range 0-171 months) was available for 87/109 (80%) patients, of whom 46 (53%) died of disease. CONCLUSION: This is the largest study to date of metastatic solid tumours secondarily involving the penis. The most frequent primaries originated from the genitourinary and gastrointestinal tracts. Metastatic penile tumours usually presented with penile nodules/masses and pain, and they often occurred in the setting of advanced metastatic disease, portending poor clinical outcomes.

Diffuse Idiopathic Pulmonary Neuroendocrine Cell Hyperplasia: Review of the Literature and a Single-center Experience.

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is a rare disorder that is commonly underdiagnosed. In 2015, it was recognized by the World Health Organization (WHO) classification of lung tumors as a premalignant lesion. DIPNECH syndrome is characterized by cough, exertional dyspnea, wheezing, and, less frequently, hemoptysis. We report the clinical and histological features and imaging findings in four cases of DIPNECH from our institution (Torrejon University Hospital, Madrid, Spain) between the years 2012 and 2019. DIPNECH represents a rare and poorly understood pulmonary disorder. Our limited single-center experience shows the slow and stable evolution of the disease. However, some exceptional cases may progress poorly if distant metastases occur.

Metastatic Thymic Carcinoma with Long Survival After Treatment with Sunitinib.

Thymic carcinomas are the most aggressive histological subtype of thymic tumors with limited data to guide correct management. No standard treatments are available for patients with advanced thymic carcinoma after progressing while on platinum-based chemotherapy. We present a case of a patient with metastatic thymic carcinoma with an unusual response and favorable evolution after receiving treatment with sunitinib, obtaining a progression-free survival of 23 months, much higher than reported to date. We review the literature on the efficacy of sunitinib in metastatic thymic carcinoma after progression to first-line treatment with platinum combinations.

A Peculiar Form of Breast Fat Necrosis Simulating Hyaline Ring Granuloma (So-called Pulse Granuloma): A Rare Complication of Hyperparathyroidism.

Pulse granuloma is a rare, foreign body inflammatory reaction that occurs mainly in the oral cavity. It is exceedingly rare elsewhere, with only isolated cases described in the literature. We report the case of a 79-year-old woman with a history of normocalcemic hyperparathyroidism who presented to our hospital with a painful 4-cm lump in the upper quadrants-upper outer quadrant of her left breast. The clinical and radiological (BIRADS-5) findings were indicative of a malignant lesion. However, core needle biopsy revealed features simulating hyaline ring granuloma (pulse granuloma-like). A definitive diagnosis of lipomembranous fat necrosis was made by identifying its characteristic histomorphology. Histopathological study is essential to establish an exact diagnosis since clinical and imaging features may mimic breast carcinoma. To our knowledge, this is the first reported case of a hyaline ring granuloma-like in the breast, which may represent a peculiar form of degenerative change of lipomembranous fat necrosis.

[Kaposi's sarcoma with colorectal and anal canal involvement]. / Sarcoma de Kaposi con afectación colorrectal y del canal anal.

Kaposi's sarcoma (KS) is a low-grade vascular tumor, with four main variants, one of which is fairly prevalent in HIV-infected patients. Mucocutaneus and lymph node involvement is characteristic. The gastrointestinal tract is involved in 40% of patients, but rectal and anal canal involvement is exceptional. We report the case of a 39-year-old HIV-infected man with an unusual presentation of KS with colorectal and anal canal involvement in the absence of cutaneous disease. The patient was treated with highly active antiretroviral therapy and systemic chemotherapy, with partial response. Local radiation therapy of the rectum produced local remission.

Differential resolution of inflammation and recovery after renal ischemia-reperfusion injury in Brown Norway compared with Sprague Dawley rats.

To investigate mechanisms conferring susceptibility or resistance to renal ischemia, we used two rat strains known to exhibit different responses to ischemia-reperfusion. We exposed proximal tubule cells isolated from Sprague Dawley or Brown Norway rats, to a protocol of hypoxia, followed by reoxygenation in vitro. The cells isolated from both rat strains exhibited comparable responses in the disruption of intercellular adhesions and cytoskeletal damage. In vivo, after 24 h of reperfusion, both strains showed similar degrees of injury. However, after 7 days of reperfusion, renal function and tubular structure almost completely recovered and inflammation resolved, but only in Brown Norway rats. Hypoxia-inducible factor-dependent gene expression, ERK1/2, and Akt activation were different in the two strains. Inflammatory mediators MCP-1, IL-10, INF-gamma, IL-1beta, and TNF-alpha were similarly induced at 24 h in both strains but were downregulated earlier in Brown Norway rats, which correlated with shorter NFkappaB activation in the kidney. Moreover, VLA-4 expression in peripheral blood lymphocytes and VCAM-1 expression in kidney tissues were initially similar at 24 h but reached basal levels earlier in Brown Norway rats. The faster resolution of inflammation in Brown Norway rats suggests that this strain might be a useful experimental model to determine the mechanisms that promote repair of renal ischemia-reperfusion injury.

ERK1/2 mediates cytoskeleton and focal adhesion impairment in proximal epithelial cells after renal ischemia.

ERK1/2 has been reported to be activated in the postischemic kidney but its precise role in ischemia/reperfusion (I/R) injury remains unclear. Therefore, we have studied the expression of ERK1/2 and its contribution to cytoskeleton organization and cell adhesion structures in proximal tubular cells, all affected during I/R. We observe ERK1/2 activation at 24 hours of reperfusion in an in vivo model of I/R, when acute tubular necrosis (ATN) is most prominent. In addition, by means of an in vitro model of hypoxia/reoxygenation (H/R) in rat proximal NRK-52E cells we show that p-ERK1/2 is strongly induced early during reoxygenation. Moreover, we also demonstrate that ROS generation contributed to this induction. ERK1/2 activation is contemporary with cell-cell adhesion disruption during reoxygenation but the use of U0126 did not have effect on adherens junctions (AJ) and tight junctions (TJ) disassembly, neither on epithelial monolayer permeability. On the contrary, ERK1/2 affects cytoskeleton organization and focal complexes assembly during H/R, since U0126 improved actin and tubulin cytoskeleton structure, reduced cell contraction and prevented paxillin redistribution. In summary, ERK1/2 signalling plays an essential role in I/R induced injury, mediating proximal cell adhesive alterations which lead to tubular damage and ultimately might compromise renal function.

Requirements for proximal tubule epithelial cell detachment in response to ischemia: role of oxidative stress.

Sublethal renal ischemia induces tubular epithelium damage and kidney dysfunction. Using NRK-52E rat proximal tubular epithelial cells, we have established an in vitro model, which includes oxygen and nutrients deprivation, to study the proximal epithelial cell response to ischemia. By means of this system, we demonstrate that confluent NRK-52E cells lose monolayer integrity and detach from collagen IV due to: (i) actin cytoskeleton reorganization; (ii) Rac1 and RhoA activity alterations; (iii) Adherens junctions (AJ) and Tight junctions (TJ) disruption, involving redistribution but not degradation of E-cadherin, beta-catenin and ZO-1; (iv) focal adhesion complexes (FAC) disassembly, entangled by mislocalization of paxillin and FAK dephosphorylation. Reactive oxygen species (ROS) are generated during the deprivation phase and rapidly balanced at recovery involving MnSOD induction, among others. The use of antioxidants (NAC) prevented FAC disassembly by blocking paxillin redistribution and FAK dephosphorylation, without abrogating AJ or TJ disruption. In spite of this, NAC did not show any protective effect on cell detachment. H(2)O(2), as a pro-oxidant treatment, supported the contribution of ROS in tubular epithelial cell-matrix but not cell-cell adhesion alterations. In conclusion, ROS-mediated FAC disassembly was not sufficient for the proximal epithelial cell shedding in response to sublethal ischemia, which also requires intercellular adhesion disruption.

Syncytial giant cell hepatitis in human immunodeficiency virus-infected patients with chronic hepatitis C: 2 cases and review of the literature.

Syncytial giant cell hepatitis (SGCH) among adult human immunodeficiency virus (HIV)-infected patients has been rarely described. Most cases have been reported in subjects coinfected with the hepatitis C virus (HCV), but its prevalence and outcome remain unknown. We performed a retrospective analysis of all cases of SGCH among 332 liver biopsies from HIV-infected patients seen at a tertiary center in Madrid, Spain, between 1984 and March 2004. Two hundred fifty specimens were obtained from HCV-coinfected patients. There were 2 cases of SGCH, leading to an observed overall prevalence of 0.6% (0.8% when considering only HCV-coinfected patients). In addition to histological changes secondary to chronic hepatitis C, the liver cords were replaced by syncytial giant cells with up to 30 nuclei. There was no histological evidence of measles (among paramyxoviruses) or herpes viruses group infections. In patient 1, there was a progressive clinical worsening after a 3-month course of prednisone, leading to liver failure and death. His postmortem liver biopsy showed more abundant giant hepatocytes accompanied with the development of a histologic pattern of severe fibrosing cholestatic hepatitis. The second patient received a prolonged course of pegylated interferon-alpha-2b and ribavirin with clearance of syncytial giant hepatocytes despite HCV-RNA persistence. SGCH is a rare histological finding among HIV-infected patients with chronic hepatitis C. Specific treatment with pegylated interferon and ribavirin can lead to histological resolution and biochemical improvement, even in the absence of HCV-RNA clearance.