Histomorphological and Immunohistochemical Reappraisal of Cutaneous Adnexal Tumours: A Hospital Based Study

Background. Diagnosing adnexal tumours of the skin is a challenge due to their wide variety, infrequent occurrence in practice, and confusing morphological picture.Aims and Objectives. The present study aims to observe the spectrum of adnexal tumours at our institute and to evaluate them based on histomorphological, histochemical, and immunohistochemical methods either alone or in combination for proper identification and classification.Materials and Methods. A partly retrospective and partly prospective study was conducted on adnexal skin tumours over a period of 6 years. Relevant clinical profile was recorded. Histopathological examination was carried out and special stains were applied as and when required. Immunohistochemistry was performed where diagnosis with routine stains was not possible.Results. A total of 150 skin tumour biopsies were received. There were 87 keratotic tumours, 39 adnexal tumours, and 24 melanocytic tumours. Amongst the adnexal tumours, 51.3% eccrine, 30.8% follicular, and 17.9% sebaceous tumours were seen. In five cases, histological diagnosis was troublesome where immunohistochemistry helped in making final diagnosis.Limitations. The sample size is small.Conclusion. Histomorphology is confirmatory in majority of the adnexal tumours but few rare lesions that mimic internal malignancy require a panel of immunomarkers to rule out other possible differentials.

Pathology Services in Developing Countries—The West African Experience

Context.—Histopathology, like other branches of medicine in West Africa, has suffered largely from economic, political, social, and infrastructural problems, becoming a shadow of the top quality that had been obtained in the past. To address the prevailing problems, one needs to attempt defining them. Objective.—The existing structure of training and practice are discussed, highlighting the author's perception of the problems and suggesting practical ways to address these while identifying potential roles for North American pathology organizations. Design.—The author's past and ongoing association with pathology practice in Nigeria forms the basis for this review. Results.—Pathology practice is largely restricted to academic medical centers. The largest of academic centers each accession around 4000 or fewer surgical specimens per year to train 9 to 12 residents. Histopathology largely uses hematoxylin-eosin routine stains, sometimes with histochemistry but rarely immunohistochemistry. Pathologists depend largely on their skills in morphology (with its limitations) to classify and subclassify tumors on routine stains, including soft tissue and hematolymphoid malignancies. Immunofluorescence, intraoperative frozen section diagnosis, electronic laboratory system, and gross and microscopic imaging facilities are generally not available for clinical use. Conclusion.—The existing facilities and infrastructure can be augmented with provision of material and professional assistance from other pathology associations in more developed countries and should, among other things, focus on supplementing residency education. Virtual residency programs, short-visit observerships, development of simple but practical laboratory information systems, and closer ties with pathologists in these countries are some of the suggested steps in achieving this goal.

Intestinal spirochetosis: first cases reported in Brazil and the use of immunohistochemistry as an aid in histopathological diagnosis

Colonization of the colon and rectum by intestinal spirochetes is detected for the first time in Brazil in 4 of 282 (1.41%) patients who had undergone sigmoidoscopy and/or colonoscopy with a histopathological diagnosis of chronic non specific-colitis. This frequency is probably understimated, since surgically obtained specimens were not considered in the present study. Histopathological diagnosis was performed using routine stains like hematoxylin-eosin which showed the typical, of 3-µm thick hematoxyphilic fringe on the brush border of the surface epithelium, and by silver stains like the Warthin-Starry stain. Immunohistochemical procedures using two, polyclonal, primary antibodies, one against Treponema pallidum and the other against Leptospira interrogans serovar copenhageni serogroup Icterohaemorrhagiae cross-reacted with spirochetal antigen/s producing a marked contrast of the fringe over the colonic epithelium, preserving the spiral-shaped morphology of the parasite. In one case with marked diarrhea, immunohistochemistry detected spirochetal antigen/s within a cell in an intestinal crypt, thus demonstrating that the infection can be more widely disseminated than suspected using routine stains. Immunohistochemical procedures, thus, greatly facilitate the histological diagnosis of intestinal spirochetosis and may contribute to a better understanding of the pathogenesis of the disease. Transmission and scanning electron microscopy performed in one case showed that the spirochete closely resembled the species designated as Brachyspira aalborgi.

Frozen-Section Autoradiography of the Cochlea: Evidence for Differential Distribution of Amino Acids

A histological method is described for embedding the whole cochlea in an egg yolk medium that permits frozen sectioning in the mid-modiolar plane. Resulting tissues can be processed using standard autoradiographic techniques and stained with Nissl or silver impregnation methods. Following identical intracochlear injections of tritiated proline or leucine and frozen sectioning of embedded cochleae, differential uptake patterns within the cochlea were revealed for these amino acids. Frozen sectioning of the cochlea promises to provide an efficient means to examine specific labeling patterns within the cochlear duct for compounds suspected of contributing to cochlear function by permitting the application of multiple histological techniques including routine stains and anterograde and retrograde tracers.