Polyphasic identification of three new species in Alternaria section Infectoriae causing human cutaneous infection.

BACKGROUND: Cutaneous phaeohyphomycosis is an emerging disease in immunocompromised patients, being Alternaria one of the most common genera reported as a causative agent. Species identification is not carried out mainly due to the complexity of the genus. Analysis of the ITS barcode has become standard for fungal identification, but in Alternaria it is only able to discriminate among species-groups or sections. METHODS: We present three cases of cutaneous infection caused by Alternaria isolates morphologically identified as belonging to section Infectoriae. They have been morphologically characterised and phylogenetically delineated with five molecular markers (ITS, ATPase, gapdh, rpb2 and tef1). RESULTS: Mycotic infections have been diagnosed by repeated cultures and histopathological examination in two of the cases. The polyphasic approach has allowed to delineate three new species of Alternaria section Infectoriae, that is A anthropophila, A atrobrunnea and A guarroi. ATPase has been the only locus able to discriminate most of the species (29 out of 31) currently sequenced in this section, including A infectoria the commonest reported species causing alternariosis. Susceptibility test showed different antifungal patterns for the three species, although terbinafine was the most active in vitro drug against these fungi. CONCLUSIONS: The ATPase gene is recommended as an alternative barcode locus to identify Alternaria clinical isolates in section Infectoriae. Our results reinforce the relevance of identification of Alternaria isolates at the species level and the necessity to carry out antifungal susceptibility testing to determine the most adequate drug for treatment.

Interdigitating dendritic cell sarcoma presenting in the nasal region.

Interdigitating dendritic cell sarcoma (IDCS) is an extremely rare neoplasm derived from antigen-presenting cells. IDCS displays aggressive behavior in a third of all cases, and the most common involvement is a solitary lymph node. We report the case of an 87-year-old woman with a right nasal mass. She underwent a wide local excision and right functional lymphadenectomy. Histopathological, immunohistochemical and molecular studies were consistent with the diagnosis of IDCS. Although it is extremely rare, this case suggests that extranodal IDCS should be considered in the differential diagnosis of undifferentiated fusiform neoplasms.

Systematic analysis of transrectal prostate biopsies using an ink method and specific histopathologic protocol: a prospective study.

Background. Transrectal prostate biopsy is the standard protocol for the screening for prostate cancer. It helps to locate prostatic adenocarcinoma and plan treatment. However, the increasing number of prostate biopsies leads to considerably greater costs for the pathology laboratories. In this study, we compare the traditional method with an ink method in combination with a systematic histopathologic protocol. Methods. Two hundred consecutive transrectal prostate biopsy specimens were received from the radiology department. They were separated into two groups: one hundred were processed as six different specimens in the usual manner. The other one hundred were submitted in six containers, the apex, base, and middle section of which were stained different colours. The samples subject to the ink method were embedded in paraffin and placed in two cassettes which were sectioned using a specific protocol. Results. The comparative study of the nonink and ink methods for histopathologic diagnosis showed no statistical differences as far as diagnostic categories were concerned (P value < .005). The number of PIN diagnoses increased when the ink method was used, but no statistical differences were found. The ink method led to a cost reduction of 48.86%. Conclusions. Our ink method combined with a specific histopathologic protocol provided the same diagnostic quality, tumor location information as the traditional method, and lower pathology expenses.