[Rosai-Dorfman-Destombes disease with a misleading laryngeal presentation]. / Une maladie de Rosai­Dorfman­Destombes de présentation laryngée trompeuse.

Rosai-Dorfman-Destombes disease is a rare non-Langerhansian cell histiocytosis characterized by the accumulation of large activated histiocytes in the affected tissues with images of emperipolesis. The diagnosis is not really problematic in the classical forms, with a lymph node presentation, whose histology is very suggestive. However, it can be much more difficult in the extra-nodal forms, which are misleading in both their clinical and histological presentation. We report here a case illustrating this diagnostic difficulty. Firstly, clinically, the disease was revealed by an unusual laryngeal location, responsible for acute obstructive respiratory distress and requiring urgent surgical management. Secondly, histologically, the diagnosis was not evoked in the first instance by analysis of the laryngeal lesion. Indeed, there was a not specific appearing polymorphic infiltrate, associating small lymphocytes, plasma cells and numerous histiocytes, without evidence for a lymphoma after immunohistochemistry and lymphocyte clonality analysis. However, after re-examination of the slides, the histiocytes sometimes appeared large or xanthomised and have a PS100+, CD1a-, langerhine- phenotype, with rare images of emperipolesis. These aspects finally suggested the diagnosis of Rosai-Dorfman-Destombes disease, then confirmed by a cervical lymph node biopsy showing characteristic histological features. Simultaneously, NGS analysis of the laryngeal lesion showed a mutation in the MAP2K1 gene, in accordance with the diagnosis. The patient was treated with revlimid and dexamethasone for 6 months, with complete remission, and is currently undergoing maintenance treatment with revlimid.

Value of cytokeratin 5/6 immunostaining using D5/16 B4 antibody in the spectrum of proliferative intraepithelial lesions of the breast. A comparative study with 34betaE12 antibody.

Previous studies have shown that basal-type cytokeratins (CKs) can distinguish usual ductal hyperplasia (UDH) from the spectrum of atypical ductal hyperplasia (ADH), ductal carcinoma in situ (DCIS) and lobular carcinoma in situ (LCIS). Indeed, expression of these CKs is weak or absent in ADH, DCIS and LCIS. However, the diagnostic usefulness of D5/16B4 antibody (anti-CK5/6) has never been compared with that of 34betaE12 antibody (anti-CK1/5/10/14). We performed immunostaining of CK 5/6 and CK1/5/10/14 on 100 breast lesions, including UDH ( n=31), ADH ( n=5), DCIS ( n=54) and LCIS ( n=10). Abundant immunostaining was observed in all UDH using both antibodies. Four of five of the ADH cases showed less than 5% of CK5/6 stained cells, the remaining case showed 30% of labeled cells. With 34betaE12 antibody, three of five of the ADH cases showed less than 5% labeled cells, while two cases showed more than 30% of stained cells. None of the 54 DCIS or the 10 LCIS was labeled by D5/16B4, while a lack of 34betaE12 immunostaining was observed in only 15 of 54 DCIS and 2 of 10 LCIS. We confirmed that D5/16B4 antibody directed against CK5/6 is useful in distinguishing UDH from the spectrum of ADH/DCIS/LCIS. We also demonstrated that D5/16B4 is far a more specific marker than 34betaE12 antibody.

Incidence of sarcoma histotypes and molecular subtypes in a prospective epidemiological study with central pathology review and molecular testing.

BACKGROUND: The exact overall incidence of sarcoma and sarcoma subtypes is not known. The objective of the present population-based study was to determine this incidence in a European region (Rhone-Alpes) of six million inhabitants, based on a central pathological review of the cases. METHODOLOGY/PRINCIPAL FINDINGS: From March 2005 to February 2007, pathology reports and tumor blocks were prospectively collected from the 158 pathologists of the Rhone-Alpes region. All diagnosed or suspected cases of sarcoma were collected, reviewed centrally, examined for molecular alterations and classified according to the 2002 World Health Organization classification. Of the 1287 patients screened during the study period, 748 met the criteria for inclusion in the study. The overall crude and world age-standardized incidence rates were respectively 6.2 and 4.8 per 100,000/year. Incidence rates for soft tissue, visceral and bone sarcomas were respectively 3.6, 2.0 and 0.6 per 100,000. The most frequent histological subtypes were gastrointestinal stromal tumor (18%; 1.1/100,000), unclassified sarcoma (16%; 1/100,000), liposarcoma (15%; 0.9/100,000) and leiomyosarcoma (11%; 0.7/100,000). CONCLUSIONS/SIGNIFICANCE: The observed incidence of sarcomas was higher than expected. This study is the first detailed investigation of the crude incidence of histological and molecular subtypes of sarcomas.