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Canine and Feline Nasal and Paranasal Neoplasm: Morphology and Origin
Published in Gerd Reznik, Sherman F. Stinson, Nasal Tumors in Animals and Man, 2017
Histomorphologic variations are seen in this group of adenocarcinomas in different neoplasms as well as in different areas of the same neoplasm. These neoplasms are composed of groups of various-sized cystic structures that contain basophilic mucoid material, are lined with small benign-looking epithelial cells, and are surrounded by connective tissue stroma resembling myoepithelial cells or stroma infiltrated with mucoid material (Figure 4). In some tumors, the mucoid material is extensive, breaking up the neoplastic cells into strands or large cystic structures with epithelial cells arranged in cribriform pattern. Cellular areas with occasional cysts are infrequently seen. The neoplastic cells are small, cuboidal, with hyperchromatic nuclei and scanty basophilic cytoplasm. Mitotic cells are rarely seen. The mucoid material is granular, basophilic, and does not stain with mucicarmine stain. In areas, desmoplasia and lymphoid cell accumulations are seen.
Intracellular and Extracellular Structures
Published in Philip T. Cagle, Timothy C. Allen, Mary Beth Beasley, Diagnostic Pulmonary Pathology, 2008
Rose C. Anton, Philip T. Cagle
Cryptococcus is a round to oval yeast averaging 5 to 10 μm in diameter. Yeast can be identified on histological sections where they appear as pale blue structures surrounded by a thick mucoid capsule (Fig. 21). On routine H&E-stained sections, the capsule is visualized as a clear halo, which is actually an artifact of processing, producing shrinkage of the capsule. GMS and PAS highlight the yeast; mucin stains, preferably mucicarmine, are used to identify the capsule (bright red on mucicarmine stain). The capsule, when present, allows the Cryptococcus to be distinguished from other small yeast. Budding is unequal and, unlike Blastomyces, Cryptococcus has a narrow base.
Primary anaplastic large cell lymphomas of the pancreas
Published in Baylor University Medical Center Proceedings, 2022
Ling Chen, John R. Krause, Haiying Zhang
A 66-year-old woman presented with abdominal pain and jaundice. Computed tomography revealed a locally invasive 5.0 × 3.9 cm mass in the porta hepatis/pancreatic head. There was no peripheral adenopathy and no involvement of liver or spleen. Subsequent magnetic resonance imaging showed the mass contiguous with the largest conglomerate of lymph nodes in the porta hepatis region. The imaging findings raised broad differentials, including primary pancreatic carcinoma, primary pancreatic lymphoma, extrahepatic cholangiocarcinoma, and metastasis. Fine needle aspiration of the pancreatic mass (Figure 2a, 2b) revealed large-sized malignant cells with abundant cytoplasm and pleomorphic, eccentric nuclei. Immunohistochemically, the tumor cells were positive for CD30 (Figure 2c) and CD4, patchy positive for CD3, and negative for CD20 and ALK (Figure 2d). The malignant cells were also negative for CK-CAM 5.2, CK19, SOX10, synaptophysin, chromogranin, as well as for mucicarmine stain and EBER. The Ki-67 proliferative index was nearly 90% in malignant cells. Diagnosis of ALK-negative ALCL was made. The patient was scheduled to receive chemotherapy at another institution.
Choroid Plexus Carcinoma with Hyaline Globules: An Uncommon Histological Finding
Published in Fetal and Pediatric Pathology, 2022
Shilpy Jha, Suvendu Purkait, Chinmaya Dash, Chinzah Lalsangzuala
A two-year-old male child presented with complaints of headache and vomiting for six months. He had one episode of seizure six months previously. The parents noticed his lower limbs appeared weak, with decreased movement for the past 15 days. On radiological examination, a contrast-enhancing tumor was located in the right temporoparietal region (Fig. 1(A)). Intraoperatively, the tumor was highly vascular and soft, with no definite cleavage plane from the normal brain parenchyma. The frozen section revealed a high-grade malignancy, and the possibilities of choroid plexus carcinoma versus anaplastic ependymoma were considered. On permanent sections, the tumor displayed a predominantly papillary pattern blurring into sheets of tumor cells. The cells exhibited marked nuclear pleomorphism, mitotic activity (3–4/10 hpf), and areas of necrosis (Fig. 1(B,C)). Many eosinophilic intracytoplasmic and extracellular hyaline globules were observed (Fig. 1(D)) that were periodic acid Schiff stain (PAS) positive and diastase resistant (Fig. 1(E)) while negative for mucicarmine stain and amyloid.
A case of HIV associated cryptococcal nephritis: Ultrastructural findings and literature review
Published in Ultrastructural Pathology, 2018
Ashley Flowers, Xin Gu, Guillermo A Herrera, Sandy Gibson, Judy King
Non-pulmonary infections generally occur from secondary dissemination from the pulmonary origin and can involve any body site or structure. Direct renal infection with Cryptococcus manifests with identifiable parenchymal infiltration by the yeast within the interstitium, tubules, and occasionally glomeruli. The yeast typically range in size from 4 to 10 µm and are surrounded by a mucinous capsule which is stainable with mucicarmine stain. In capsule-deficient yeast, the Fontana-Masson stain highlights melanin contained in the yeast. In an immunocompetent patient, there is usually severe interstitial inflammation composed of lymphocytes, macrophages, and foreign body giant cells surrounding the organisms. In immunocompromised patients, there may be minimal inflammatory reaction.5,6 In the present case, disseminated cryptococcosis was known at the time of the renal biopsy, and organisms were identified infiltrating the interstitium, tubules, and glomeruli with an accompanying predominant histiocytic reaction. No well-formed granulomas or multinucleated giant cells were seen. Additionally, the yeast were identified by coating of the capsule wall with C3 by immunofluorescent microscopy and they were also visualized by electron microscopy in the glomerular capillary lumens, interstitium, and tubular epithelium. Only low-level proteinuria was present in the current case however; infiltration of glomeruli by cryptococci has been reported in association with nephrotic range proteinuria. It has been suggested that intracapillary release of inflammatory mediators due to the presence of intracapillary cryptococci cause foot process effacement and the clinical manifestation of nephrotic range proteinuria.5