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Brain
Published in Joseph Kovi, Hung Dinh Duong, Frozen Section In Surgical Pathology: An Atlas, 2019
Joseph Kovi, M.D. Hung Dinh Duong
Perhaps the only entity which presents problems in the differential diagnosis is metastatic squamous cell carcinoma especially if the frozen sections are not of very good quality. Both meningioma and squamous cell carcinoma form large, solid cell nests. The tumor cells may have poorly defined outlines. The cytoplasm in both the meningothelial cells and the squamous carcinoma cells is quite acidophilic. Therefore, the cell nests of a meningotheliomatous meningioma may resemble the cell clusters found in squamous cell carcinoma. The major differential diagnostic criteria are (1) The nuclei of the meningothelial cells are highly regular usually ovoid. Squamous carcinoma cells have pleomorphic nuclei. (2) Mitotic activity is virtually absent in meningioma but common in carcinoma. (3) Necrosis is not found in meningioma; it is frequent in squamous cell carcinoma. (4) Small blood vessels have a hyalinized thickened wall in meningioma. The blood vessels in carcinoma are usually quite delicate. (5) Psammoma body formation is characteristic of meningioma; only granular, coarse, or powdery calcium deposits are found in carcinoma.
Differentiated thyroid carcinoma
Published in David S. Cooper, Jennifer A. Sipos, Medical Management of Thyroid Disease, 2018
Carolyn Maxwell, Jennifer A. Sipos
Encapsulated follicular variant papillary cancers (eFVPTC) have a very indolent clinical course. Those tumors that show no evidence of invasion have a behavior that is consistent with a non-cancerous lesion, similar to a follicular adenoma (99). In contrast, invasive FVPTC has a clinical course similar to that seen in the classic variant of PTC. Molecular profiles also confirm a distinction between the invasive and noninvasive tumors. The noninvasive FVPTC tumors have a molecular signature akin to follicular adenomas, whereas invasive FVPTCs harbor mutations similar to that seen in PTC (11). To prevent over-treatment of the indolent, noninvasive tumors, an international, multidisciplinary group was convened to perform a clinicopathologic survey of 268 cases of FVPTC and examine the long-term outcomes (100). The authors compared the clinical course of 138 noninvasive lesions with that of 130 invasive tumors. After a median follow-up of 13 years, all of the patients with noninvasive tumors were alive without evidence of residual or recurrent disease. In contrast, the invasive eFVPTC group had two deaths due to disease, five patients developed distant metastases, seven cases were identified with persistent/recurrent disease, and five patients had biochemical evidence of persistent disease during 3.5 years of follow up. The conclusion of this analysis was that a change in nomenclature for the noninvasive tumors from carcinoma was warranted; the group defined these tumors instead as “noninvasive follicular neoplasms with papillary-like nuclear features” or NIFTP (100). The diagnostic criteria include a well-demarcated tumor that is distinct from the normal thyroid parenchyma. There should be no evidence of tumor invasion into the surrounding normal thyroid tissue or tumor capsule (when present). Likewise, there should be no perineural or angiolymphatic invasion or extrathyroidal extension. The tumor must show a follicular architecture, with no well-formed papillary structures within the tumor (101). The presence of a psammoma body, or infarcted papilla, is an exclusion for the diagnosis of NIFTP. The nuclear features are those seen in papillary carcinoma, but typically are subtler and may be diffuse or patchy in distribution (100).
Differentiation and plasticity of human vascular wall mesenchymal stem cells, dermal fibroblasts and myofibroblasts: a critical comparison including ultrastructural evaluation of osteogenic potential
Published in Ultrastructural Pathology, 2019
Emanuela Pasanisi, Carmen Ciavarella, Sabrina Valente, Francesca Ricci, Gianandrea Pasquinelli
The osteogenic differentiation was performed for 21 days culturing the cells with a specific induction media. Alizarin Red staining after stimulation revealed a marked mineralization process in all the analyzed cells, with a higher intensity in dermal fibroblasts and WPMY-1 than hVW-MSCs (Figure 5(a)). Ultrastructural investigation confirmed the mesenchymal characteristics of the investigated cells. As seen in Figure 5(b–d), control MSCs, fibroblasts and WPMY-1 had a high N/C ratio with euchromatic nuclei and evident nucleoli; the cytoplasm was scant and contained few organelles. After osteogenic induction, each cell type underwent mineralization, as shown in representative images in Figure 5(b–d). However, substantial differences were also observed. Femoral MSCs were associated with numerous fully mineralized vesicles engulfed with hydroxyapatite crystals (Figure 5(b)), a pattern already well described in the early phase of bone calcification;35,36 dermal fibroblasts exhibited a lamellar calcification with prominent psammoma body formation (Figure 5(c)); in this case confluent concentric calcifications were seen around or overlying foci of degenerated cell fragments; WPMY-1 showed intensive collagenic matrix deposition with hydroxyapatite crystals encrusting individual or clustered collagen fibers (Figure 5(d)). The present data suggest that these cells underwent distinct mechanisms of osteogenic differentiation and mineralization.