[Bullous dermatitis with multinucleated keratinocytes in dermatitis artefacta: A case report]. / Dermatose bulleuse avec kératinocytes multinucléés révélant une dermatose factice : à propos d'un cas et revue de la littérature.

We report the case of a 13-year-old young lady with a one year reccuring bullous dermatitis history for which the diagnostic hypothesis of dermatitis arterfacta was made. This hypothesis was made by the pathologist, without it being suggested by the dermatologist, after observing singular histological lesions coresponding to a cutaneous blister associated with epidermic necrosis with multinucleated keratinocytes. When dermatitis artefacta is suspected, a biopsy is usually conducted to rule out differential diagnosis such as auto-immmune dermatitis when there is a blister. Confession from patients is rarely obtained. Therefore, having positive histogical clues for dermatitis artefacta would be of a great use to help making the diagnosis in difficult cases.

[Microcystic serous cystadenoma: An uncommon neoplasm of pancreas. Report of two cases]. / Cystadénome séreux microkystique : une tumeur rare du pancréas. À propos de deux observations.

Microcystic variant of serous cystadenoma of the pancreas is a rare neoplasm; essentially located in the body or tail of the pancreas and associated with the von Hippel-Lindau. Often, patients are asymptomatic and the neoplasm is incidentally discovered. Usually radiographic manifestations are characteristic. Histopathological examination revealed uniform clear cuboidal cells; they can be confused with other clear cell neoplasms like renal cell carcinomas, well-differentiated neuroendocrine tumors and solid pseudopapillary tumors of the pancreas. Immunohistochemistry can be help to establish the diagnosis and to remove differential diagnosis. Serous cystadenoma is a benign neoplasm whose prognosis is excellent. We herein report two cases of microcystic serous cystadenomas of the pancreas diagnosed in two asymptomatic women and review analysis in the literature to remind the main features of this lesion and the main differential diagnosis.

Somatostatin Receptors 2A and 5 Are Expressed in Merkel Cell Carcinoma with No Association with Disease Severity.

BACKGROUND/AIMS: Merkel cell carcinoma (MCC) is a rare high-grade neuroendocrine tumour of the skin. It has been speculated that MCCs express somatostatin receptors (SSTRs), but this has never been assessed in a large series of MCCs. The main aim of this study was to assess the expression of SSTR2A and SSTR5 in MCC tumours. The secondary aims were to assess whether expression of SSTR was associated with the Ki67 proliferative index, Merkel cell polyomavirus (MCPyV) status, clinical characteristics and outcome. METHODS: Clinical data and tumours were collected from an ongoing cohort of French patients with MCC. Immunohistochemistry was performed with anti-SSTR2A and anti-SSTR5 monoclonal antibodies, and tumours were classified into 3 groups: 'no expression', 'low expression' and 'moderate expression' using an SSTR staining score. RESULTS: SSTR expression was assessed for 105 MCC tissue samples from 98 patients, and clinical characteristics were available for 87 of them. SSTR expression was consistent between the primary skin tumour and the corresponding metastases for SSTR2A and SSTR5 in 3/7 and 6/7 cases, respectively. SSTR2A and SSTR5 were expressed in 58 cases (59.2%) and in 44 cases (44.9%), respectively. Overall, at least one SSTR was expressed in 75 tumours (76.5%). SSTR expression was not associated with clinical characteristics, Ki67 proliferative index, recurrence-free survival or MCC-specific survival. Expression of SSTR2A was associated with MCPyV status in MCC tumours but not SSTR5. CONCLUSION: SSTRs were expressed in a high proportion of MCCs, although expression was heterogeneous between tumours and was not associated with disease severity.

[Gastro-intestinal neuroectodermal tumor (GNET): A case report of a small intestine tumor with hepatic metastases]. / Tumeur neuroectodermique gastro-intestinale (GNET) : à propos d'un cas de tumeur du grêle avec métastases hépatiques.

The gastro-intestinal neuroectodermal tumor (GNET) is a rare sarcoma of the digestive tract, which was recently recognised. The knowledge of the morphological, immunohistochemical and molecular diagnostic criteria is necessary to not mistake it for the metastasis of a melanoma or for another sarcoma of the digestive tract as the gastro-intestinal clear cells sarcoma or the malignant peripheral nervous system tumor (MPNST). We report the case of a 41-year-old patient with a GNET of the small intestine with hepatic metastasis. The histological examination showed a diffuse proliferation of epithelioid cells, which only express PS100. The presence EWSR1-ATF1 gene fusions with any melanocytic differentiation leads to the diagnosis of GNET.

[Colonic ulcers associated with taking Kayexalate(®) (sodium polystyrene sulfonate): about two cases]. / Ulcérations coliques associées à la prise de Kayexalate(®) (polystyrène sulfonate de sodium) : à propos de deux observations.

We report two cases of patients with chronic renal failure showing rectal bleeding due to digestive ulcers, associated with Kayexalate(®) alone. Kayexalate(®) crystals correspond to a typical histological picture and it is important to know how to identify them in order to discuss a possible pathogenicity.

[Cutaneous lymphoid hyperplasia (pseudolymphoma) on the red dye of a tattoo]. / Hyperplasie lymphoïde chronique (pseudolymphome) sur l'encre rouge de tatouage.

Cutaneous lymphoid hyperplasia (pseudolymphoma) on tattoo is rare. The diagnosis is histological. We report a case of cutaneous lymphoid hyperplasia within the red ink of a tattoo found on a 35-year-old man presenting multiple infiltrated nodules confined to the red areas of his tattoo, which he had done 2 months ago. The pathological examination showed a diffuse lympho-histiocytic dermo-hypodermal infiltrate, associated with a lichenoid reaction. Immunohistochemistry displayed T-cell infiltration (CD3+, CD5+, CD8+). The treatment is difficult, knowing that the spontaneous regression seems possible, and the progression into a lymphoma is exceptional in the case of a chronic evolution over a number of years.

[Hemophagocytic lymphohistiocytosis associated with a lymphohistiocytic pattern anaplastic large cell lymphoma: a case report]. / Syndrome d'activation macrophagique révélant un lymphome anaplasique à grandes cellules de variante lymphohistiocytaire : à propos d'un cas.

We report the case of a 16-year-old girl with an anaplastic large cell lymphoma of lymphohistiocytic pattern revealed by a hemophagocytic syndrome. Histologically, the lymphomatous population was concealed by clusters of histiocytes. Immunohistochemical study allowed the diagnosis. The combination of these two entities is rarely described and may be a source of delay in diagnosis of a life-threatening condition.

[Second expert review on lymphoma: assessment of a one year activity in a general hospital]. / Expertise systématique des lymphomes diagnostiqués au cours d'une année d'activité d'un centre hospitalier : évaluation.

A standardized second histological review for lymphomas was established by the French National Cancer Institute in 2010. The objective of our study was to assess the clinical impact of this process between a general hospital (reader 1) and an expert (reader 2). This prospective study was conducted between April 1st 2010 and April 1st 2011. Fifty-four cases of lymphoma were subjected to an expert review following the "LYMPHOPATH" recommendations and diagnoses of readers 1 and 2 were compared according to the WHO 2008 classification of lymphomas. We distinguished serious discrepancies (lymphoma versus other malignancy) from subtyping disagreement with or without impact on therapeutic strategy. We also determined the delays between the initial reception of the sample and reader 1's (period A) and reader 2's (period B) reports, respectively. Any additional analysis performed by second reader was also reported. Our study revealed one case of subtyping discordance (1.85%). The mean delays were 7 days for period A and 20 days for period B, respectively. Additional immunohistochemical techniques were requested by reader 2 in 11 cases (20.4%). These data provide evidence to suggest that in our department, a second review targeted on difficult diagnoses, rare lymphomas or when further analyses are required would be more relevant than a standardized second review.

[Cytological diagnostic challenge: two hyalinizing trabecular tumor case reports]. / Difficultés diagnostiques en cytopathologie thyroïdienne : à propos de deux cas de tumeur trabéculaire hyalinisante.

Hyalinizing trabecular tumors (HTT) are very rare thyroid tumors whose diagnosis is difficult, particularly in cytology. They are frequently diagnosed as papillary carcinomas due to the cytological similarities between those two tumors (anisocariosis, intranuclear cytoplasmic inclusions, nuclear grooves and nuclear overlapping). Here, we report two HTT cases which were initially diagnosed as papillary carcinoma, on the preoperative cytology and for which the patients underwent total thyroidectomy with lymph node dissection. From these two cases and a literature review, we have searched for diagnostic criteria which could increase the sensitivity of HTT diagnosis in thin layer cytology. We have found that only the identification of the fibrillar and hyaline material within the cellular cluster of the HTT seems discriminating between both tumors, even though it is difficult to diagnose it is difficult to diagnose on thin layer cytology. One major help for the diagnosis would be the typical membranous and cytoplasmic MIB-1 immunostaining. However, no experiment has been undertaken with thin layer smears for HTT.

[Tumor-to-tumor metastasis: report of three cases]. / Métastases d'une tumeur dans une autre tumeur : à propos de trois cas.

Tumor-to-tumor metastasis is a very rare event. We report three cases of tumor metastasizing in another tumor: a clear cell renal cell carcinoma in a vesicular thyroid adenoma, a lung carcinoma in a meningioma and a neuroendocrine lung carcinoma in a clear cell renal cell carcinoma. According to the literature, clear cell renal cell carcinoma is the most common tumor recipient of metastasis while lung carcinoma is the most common donor tumor. Several physiopathological mechanisms can explain this phenomenon, but many of them are still unknown.

[Request of second opinion for difficult diagnosis in surgical pathology. Assessment of a one year activity in a general hospital]. / Evaluation des demandes d'avis à un expert pour lésions de diagnostic difficile en anatomie et cytologie pathologiques. Analyse d'une année d'activité dans un service hospitalier.

OBJECTIVE: The objective of this study was to evaluate our practices concerning difficult lesions sent for second opinion to an expert. MATERIAL AND METHODS: We analyzed retrospectively all the requests for second opinion carried out over one year in our laboratory. The following data were indexed: organ, pathology (tumoral or not), type of sampling, the time, additional techniques carried out by the expert and comparison of the initial diagnosis with that of the expert. A provisional report was systematically performed before sending the observation to the expert. RESULTS: Among the 54 cases, 40 lesions were tumoral and 31 malignant. The type of pathology which were more often sent for opinion were lymphomas (18.5%) and soft tissue tumors (11%). The average time between reception of the sampling in our laboratory and the answer of the expert was 32.8 days. In 40.7% of the cases, additional techniques like immunohistochemistry (19 cases) or molecular biology (7 cases) were carried out by the expert and concerned especially lymphomas or soft tissue pathology. The comparison of the initial diagnosis with that of the expert showed no change in 53.7% of cases, 13% of divergence from benign-malignant (6 cases) or malignant-benign (1 case) type, 16.7% of changes of classification without modification of the benignity or the malignity, and 16.7% of difficult interpretation. CONCLUSION: This study seems to be a good means of evaluating our professional practices related to difficult lesions and confirms the importance of deep-freezing tumors, holding multidisciplinary meetings and participating in specialized working groups.