Ultrastructural Examination of a Case of Pagetoid Bowen Disease Exhibiting Immunohistochemical Features in Common With Extramammary Paget Disease.

A panel of immunohistochemical markers may be used to differentiate between pagetoid Bowen disease (PBD) and primary extramammary Paget disease (EMPD) in selected cases. Although diffuse staining with cytokeratin 7 (CK7), CAM5.2, carcinoembryonic antigen, epithelial membrane antigen (EMA), and gross cystic disease fluid protein 15 generally supports diagnosis of EMPD, cases have been reported where PBD also expressed CK7, EMA, and CAM5.2. Based on these findings, some authors suggested that the 2 entities may arise from the same multipotent stem cell, capable of further differentiation toward squamous and secretory lines. To the best of our knowledge, this issue has never been investigated by comparing PBD and EMPD at the ultrastructural level. We performed the first ultrastructural study of a case of PBD exhibiting common immunohistochemical features with EMPD. The lesion displayed some ultrastructural features often observed in Bowen disease and some that are typically found in EMPD. These findings indicate the presence of a bidirectional differentiation--secretory and squamous--within the same lesion, thus supporting the hypothesis that PBD and primary EMPD may arise from a common progenitor cell.

Vogt-Koyanagi-Harada disease and vitiligo: where does the illness begin?

Vogt-Koyanagi-Harada (VKH) disease is a disorder affecting melanocytes of the skin, ocular, auditory and central nervous system. The pathogenesis is thought to be related to an aberrant T cell-mediated immune response directed against self-antigens present in melanocytes. Vitiligo is characterized by leukoderma arising at any age but usually before 30 years of age. The pathogenesis of vitiligo still remains puzzling; many hypotheses have been proposed, such as autoimmune, genetic, autocytotoxic, neural and each may contribute having its own important pathogenetic role. The expressions of the most representative melanocytic markers as HMB-45, tyrosinase, S-100 protein were investigated on the lesional, perilesional and healthy skin of a patient affected by VKH and his young daughter with vitiligo. An electronmicroscopy (EM) study was performed on the same clinical specimens. Immunohistochemical data for melanocytic cells using HMB-45 and tyrosinase were negative in the VKH patient, while the expression of both HMB-45 and tyrosinase was detected in the perilesional and lesional skin of the vitiligo patient. By EM, it was possible to show many Langerhans cells (LC) in many differentiative phases, most of which with irregular cristae or matrix swelling in both the ultraviolet (UV)-exposed and non-UV-exposed skin of VKH lesions. In both vitiligo and VKH lesions, there is a disappearance of melanocytes and an alteration of LC distribution and mitochondrial morphology which may impair the antigen-presenting functions. The vitiligo lesions in the patient's young daughter question the VKH inheritability.

Oncocytic meningioma: report of a case with progression after radiosurgery.

Oncocytic meningioma is an uncommon variant of meningioma, characterized histologically by cells rich in mitochondria. This subtype of meningioma needs to be distinguished from other types of meningioma because of its more aggressive behavior. A case of oncocytic meningioma showing rapid clinical progression with diffuse intracranial dissemination after radiosurgery is described. Resistance to radiotherapy has been previously reported in oncocytic tumors of various body sites. This new case is a further example of the greater aggressiveness of oncocytic meningioma, suggesting that radiation therapy might worsen the course of disease.

Oncocytic modifications in rectal adenocarcinomas after radio and chemotherapy.

The purpose of the study is to highlight oncocytic modifications in rectal adenocarcinomas and evaluate a possible correlation with preoperative radiochemotherapy (RCT). Twenty-eight cases of advanced rectal carcinoma, treated preoperatively by 5-fluorouracil (200-225 mg/m(2)) and 44-46 Gy in 22-23 fractions, were studied. All patients underwent biopsy before RCT. Surgery was performed within 6 weeks after RCT. In all cases oncocytic modifications were searched for on hematoxylin and eosin (H&E) and at immunohistochemistry using an antimitochondrial antibody. In addition, in two cases, both pre- and post-RCT tissues were examined at electron microscopy. All tumors were adenocarcinomas. In pre-RCT biopsies, oncocytic changes were difficult to find on H&E, while the antimitochondrial antibody strongly stained numerous neoplastic cells (mean 48.4%). In post-RCT surgical specimens, oncocytic changes were detected in 24 out of 28 cases on H&E and the antimitochondrial antibody stained most of the residual neoplastic cells (mean 76.7%). Ultrastructural examination revealed large and bizarre mitochondria inside tumor cells both in pre- and post-RCT tissues. In conclusion, the present data suggest that rectal adenocarcinomas are "mitochondrion-rich" tumors. After preoperative RCT, residual neoplastic cells acquire a definite oncocytic phenotype.

Merkel cells in the oral mucosa.

Ninety-eight consecutive surgical biopsies of oral mucosa from 96 patients were evaluated immunohistochemically with an anti-cytokeratin 20 (CK 20) anti-body to evidence Merkel cells (MC). Fifteen cases, showing the highest number of MC, were additionally studied with chromogranin A, S-100 protein, neuro filaments, epithelial membrane antigen, and double immunostaining for CK 20 and Ki67 antibodies to evaluate MC proliferation. Electron microscopy was performed in 2 cases. MC were observed in 58 cases. The highest number of MC was found in the gingival, buccal, and palate mucosa, especially in chronically damaged oral mucosa (lichen and chronic aspecific inflammation) as well as in the mucosa overlying tumors rather than in normal or acute inflammation. MC were not observed in dysplastic or neoplastic epithelium. MC showed evidence of proliferation, as demonstrated by Ki67 positivity, in 3 cases. In conclusion, MC appear to play a role in the reparative processes of oral mucosa.

Basaloid carcinoma of the pancreas.

A case of basaloid carcinoma of the pancreas in a 26-year-old woman is reported. The tumour was constituted by solid nests of relatively uniform neoplastic cells with hyperchromatic nuclei and scant cytoplasm, showing distinct peripheral palisading. There were necrotic areas and deposition of hyaline material, suggesting a basement membrane-like substance. Small foci of clear-cut squamous differentiation were present. Tumour cells were positive for cytokeratin 14 and P63 and negative for neuroendocrine and acinic cell markers. Ultrastructurally, the tumour was constituted by polygonal cells with round nuclei containing clumped chromatin. Occasional tight junctions and keratin filaments were present. Basaloid carcinomas may arise in several sites of the body, the most frequent being the anus and oesophagus, and have poor clinical outcome. The present case appears to be, to the best of our knowledge, the first documented example in the literature of basaloid carcinoma of the pancreas.

Pigmented mucoepidermoid carcinoma of the oral cavity: a case report.

Melanocytes are normally present in the oral mucosa, but unlike the skin, melanocytic colonization and pigmentation of nonmelanocytic tumors rarely occur. A case of pigmented mucoepidermoid carcinoma (MEC) in a 36-year-old woman is reported. On H&E-stained sections, brownish granules were seen in intermediate and epidermoid neoplastic elements and in elongated or dendritic cells showing histologic and immunohistochemical features of melanocytes. Ultrastructurally numerous epithelial cells contained large aggregates of melanin granules, a feature suggestive of phagocytosis. In addition small individual melanin granules were observed at the external border of the epithelial cell membrane. These features suggest that melanocytes colonized the MEC and that neoplastic cells may phagocytose the granules, similarly to what occurs with epidermal melanocytes. The phenomenon of melanocyte colonization of nonmelanocytic tumors should be taken into consideration in dealing with pigmented lesions of the oral cavity.

Toker cells are probably precursors of Paget cell carcinoma: a morphological and ultrastructural description.

The present paper documents an investigation of the morphology, immunohistochemistry, and ultrastructure of Toker cells (TC), aiming for a better definition of these elements and better understanding of their histogenesis. We studied 12 nipples removed for nipple adenoma from twelve patients and a case of supernumerary nipple. In addition four cases of Paget's carcinoma (PC) restricted to the nipple without underlying tumor were studied for comparison. All cases were stained with hematoxylin and eosin (H&E), Alcian blue pH 2.5 and periodic acid-Schiff (PAS) preceded by diastase digestion and with immunohistochemistry using antisera anti cytokeratin 7, cytokeratin 20, protein S100, GCDFP-15, c-Erb-B2, CAM 5.2, and epithelial membrane antigen (EMA). Two cases from the nipple adenoma series were studied by electron microscopy. In seven cases within the series of 12 nipple adenomas as well as in the case of supernumerary nipple, keratin 7 antibody highlighted numerous cells located within the nipple epidermis which in three cases showed dendritic processes. These same elements were also positive with CAM 5.2. All these same elements were negative with Alcian Blue (AB), PAS and the other antisera employed. Ultrastructural examination demonstrated that these cells differed from keratinocytes while they presented the same features as the glandular cells seen in the related nipple adenoma. The cells constituting Paget's carcinoma showed more irregular nuclei and were more easily seen in the context of the epidermis. The immunocytochemical profile of the cancer cells was similar to that of TC, but in addition the neoplastic cells were c-Erb-B2 and EMA positive in all cases, and one case also displayed numerous cells immunoreactive with anti GCDFP-15 antibody. Keratin 7 highlighted dendritic cells in two cases and AB, PAS was negative in all patients. The immunocytochemical profile and the ultrastructural features of TC are similar to those of the glandular cells constituting the ducts and the adenoma. These findings together with the localization of TC near or around the openings of the lactiferous sinuses indicate that TC might be ductal cells with a dendritic aspect and migrate through the galactophorous ostia. PC cells not related to ductal carcinomas have a similar but not superimposable immunohistochemical profile to TC, and in two cases the neoplastic elements were also dendritic which suggests that these same cells are likely to be the neoplastic counterpart of TC.

Cytogenetic analysis of myoepithelial cell carcinoma of salivary gland.

Myoepithelial cell carcinoma (MCC) of the salivary gland is a rare entity. Here, we describe the karyotype of MCC. The patient was a 53-year-old man, with a rapidly growing lesion of the palate. Despite complete surgical excision, radio- and chemotherapy, the lesion rapidly harboured local and distant metastases leading to the death of the patient, 4 months after the diagnosis. On histological and ultrastructural examination, the primary tumour and the related metastases were composed of oval and spindle cells, with features of myoepithelial cell differentiation reported in the literature. Cytogenetic analysis showed a composite karyotype in the primary tumour: 45-46,XY, +3[cp3]/ 44-45,XY, -17[cp4]/ 46,XY[5]. The lymph-node metastasis was near-triploid and showed a complex karyotype. Our cytogenetic data differ from those described in benign or slowly growing salivary gland tumours showing myoepithelial cell differentiation. It is suggested that highly aggressive tumours might follow a different pathway of malignant transformation.

Respiratory complex I is essential to induce a Warburg profile in mitochondria-defective tumor cells.

BACKGROUND: Aerobic glycolysis, namely the Warburg effect, is the main hallmark of cancer cells. Mitochondrial respiratory dysfunction has been proposed to be one of the major causes for such glycolytic shift. This hypothesis has been revisited as tumors appear to undergo waves of gene regulation during progression, some of which rely on functional mitochondria. In this framework, the role of mitochondrial complex I is still debated, in particular with respect to the effect of mitochondrial DNA mutations in cancer metabolism. The aim of this work is to provide the proof of concept that functional complex I is necessary to sustain tumor progression. METHODS: Complex I-null osteosarcoma cells were complemented with allotopically expressed complex I subunit 1 (MT-ND1). Complex I re-assembly and function recovery, also in terms of NADH consumption, were assessed. Clones were tested for their ability to grow in soft agar and to generate tumor masses in nude mice. Hypoxia levels were evaluated via pimonidazole staining and hypoxia-inducible factor-1α (HIF-1α) immunoblotting and histochemical staining. 454-pyrosequencing was implemented to obtain global transcriptomic profiling of allotopic and non-allotopic xenografts. RESULTS: Complementation of a truncative mutation in the gene encoding MT-ND1, showed that a functional enzyme was required to perform the glycolytic shift during the hypoxia response and to induce a Warburg profile in vitro and in vivo, fostering cancer progression. Such trigger was mediated by HIF-1α, whose stabilization was regulated after recovery of the balance between α-ketoglutarate and succinate due to a recuperation of NADH consumption that followed complex I rescue. CONCLUSION: Respiratory complex I is essential for the induction of Warburg effect and adaptation to hypoxia of cancer cells, allowing them to sustain tumor growth. Differently from other mitochondrial tumor suppressor genes, therefore, a complex I severe mutation such as the one here reported may confer anti-tumorigenic properties, highlighting the prognostic values of such genetic markers in cancer.

Oncocytic carcinoma of the breast: frequency, morphology and follow-up.

Oncocytic breast carcinomas are tumors composed of no fewer than 70% of oncocytic cells (World Health Organization). The purpose of this study was to determine the frequency, morphologic, immunohistochemical, and clinical features of invasive oncocytic carcinoma in a large series. Twenty-eight cases of putative oncocytic breast carcinoma (selected cases group) and 76 consecutive cases of invasive breast carcinoma (consecutive cases group) were analyzed. Immunohistochemistry for mitochondria, gross cystic disease fluid protein 15, chromogranin, estrogen receptor, progesterone receptor, androgen receptor, HER2/Neu, cytokeratin 7, cytokeratin 14, epithelial membrane antigen, and differentiation cluster 68 was performed. Score for mitochondria was based on intensity and percentage of immunopositive cells. Classes were as follows: (1) oncocytic carcinoma: at least 70%, 3+; (2) mitochondrion-rich carcinoma: 50% to 70%, 3+, or more than 50%, 2+; and (3) all the other cases were referred to as invasive breast carcinoma. Ultrastructural examination was available for 6 cases of oncocytic carcinoma. Morphologic and immunohistochemical features of the 3 groups were compared using Fisher exact test (P < .05). For overall survival analysis, Kaplan-Maier curves were compared using log-rank and Wilcoxon tests (P < .05). Our results suggest that oncocytic breast carcinoma is a morphologic entity with distinctive histologic and ultrastructural features. Mitochondrion-rich carcinomas are histologically similar to oncocytic carcinomas and constitute 19.7% of all invasive carcinomas, indicating that cytoplasmic eosinophilia in breast cancer cells is often due to accumulation of mitochondria. Oncocytic carcinomas and mitochondrion-rich carcinomas are more often grade III tumors and show human epidermal growth factor receptor 2 overexpression. Clinical features and overall survival of oncocytic carcinomas are not distinctive because they are similar to those of the other cases when matched for grade and stage.

Genetic markers of oral malignant melanoma analysed by fluorescence in situ hybridisation (FISH).

Oral malignant melanoma (OMM) is a rare condition, and our knowledge about morphological and genetic modifications is scanty and incomplete. The aim of this study is to report morphological and fluorescent in situ hybridisation (FISH) data obtained in four cases of OMM. FISH results were also compared with those of cutaneous malignant melanoma (CMM, three cases), desmoplastic cutaneous melanoma (DMM, four cases) and spindle cells cutaneous melanoma (SCCM, one case). All the OMM cases showed a combined radial and vertical growth pattern, with the invasive component characterised by malignant spindle cells intermingled among collagen bundles. Two cases of OMM resulted positively stained with p16, in contrast with frequent loss of immunoreactivity in CMM. Three OMM were suitable for FISH analysis: 9p21 locus was deleted in 1/3, 1p36 resulted deleted 3/3, while EGFR gene showed a relative deletion. Similar genetic alterations were found in DMM and SCMM, but not in CMM. Ultrastructural findings further enhanced differences between OMM and CMM; OMM displayed, mature-staged melanosomes only within in situ component. In conclusion, OMM presents a morphological and genetic profile similar to DMM; and SCCM, however, displays some differences from CMM.

A mutation threshold distinguishes the antitumorigenic effects of the mitochondrial gene MTND1, an oncojanus function.

The oncogenic versus suppressor roles of mitochondrial genes have long been debated. Peculiar features of mitochondrial genetics such as hetero/homoplasmy and mutation threshold are seldom taken into account in this debate. Mitochondrial DNA (mtDNA) mutations generally have been claimed to be protumorigenic, but they are also hallmarks of mostly benign oncocytic tumors wherein they help reduce adaptation to hypoxia by destabilizing hypoxia-inducible factor-1α (HIF1α). To determine the influence of a disassembling mtDNA mutation and its hetero/homoplasmy on tumorigenic and metastatic potential, we injected mice with tumor cells harboring different loads of the gene MTND1 m.3571insC. Cell cultures obtained from tumor xenografts were then analyzed to correlate energetic competence, apoptosis, α-ketoglutarate (α-KG)/succinate (SA) ratio, and HIF1α stabilization with the mutation load. A threshold level for the antitumorigenic effect of MTND1 m.3571insC mutation was defined, above which tumor growth and invasiveness were reduced significantly. Notably, HIF1α destabilization and downregulation of HIF1α-dependent genes occurred in cells and tumors lacking complex I (CI), where there was an associated imbalance of α-KG/SA despite the presence of an actual hypoxic environment. These results strongly implicate mtDNA mutations as a cause of oncocytic transformation. Thus, the antitumorigenic and antimetastatic effects of high loads of MTND1 m.3571insC, following CI disassembly, define a novel threshold-regulated class of cancer genes. We suggest these genes be termed oncojanus genes to recognize their ability to contribute either oncogenic or suppressive functions in mitochondrial settings during tumorigenesis.

Disruptive mitochondrial DNA mutations in complex I subunits are markers of oncocytic phenotype in thyroid tumors.

Oncocytic tumors are a distinctive class of proliferative lesions composed of cells with a striking degree of mitochondrial hyperplasia that are particularly frequent in the thyroid gland. To understand whether specific mitochondrial DNA (mtDNA) mutations are associated with the accumulation of mitochondria, we sequenced the entire mtDNA in 50 oncocytic lesions (45 thyroid tumors of epithelial cell derivation and 5 mitochondrion-rich breast tumors) and 52 control cases (21 nononcocytic thyroid tumors, 15 breast carcinomas, and 16 gliomas) by using recently developed technology that allows specific and reliable amplification of the whole mtDNA with quick mutation scanning. Thirteen oncocytic lesions (26%) presented disruptive mutations (nonsense or frameshift), whereas only two samples (3.8%) presented such mutations in the nononcocytic control group. In one case with multiple thyroid nodules analyzed separately, a disruptive mutation was found in the only nodule with oncocytic features. In one of the five mitochondrion-rich breast tumors, a disruptive mutation was identified. All disruptive mutations were found in complex I subunit genes, and the association between these mutations and the oncocytic phenotype was statistically significant (P=0.001). To study the pathogenicity of these mitochondrial mutations, primary cultures from oncocytic tumors and corresponding normal tissues were established. Electron microscopy and biochemical and molecular analyses showed that primary cultures derived from tumors bearing disruptive mutations failed to maintain the mutations and the oncocytic phenotype. We conclude that disruptive mutations in complex I subunits are markers of thyroid oncocytic tumors.