De Novo Histoid Leprosy With Unusual Histological Features.

Histoid leprosy is a type of multibacillary leprosy that has unique clinical and histological characteristics. Some consider it to be an entity of its own, whereas others view it as a variant of lepromatous leprosy. Histoid leprosy can either occur 'de-novo', or secondarily in patients who relapse after dapsone monotherapy or in the presence of dapsone resistance. Here is a case that presented with clinical features of histoid leprosy but also with classic histologic features of lepromatous leprosy, deeming it very distinctive and unusual.

Cutaneous Mycobacteriosis Caused by Mycobacterium kansasii in a Yellow-naped Amazon Parrot (Amazona auropalliata).

An approximately 25-year-old, female, yellow-naped Amazon parrot (Amazona auropalliata) was evaluated for a chronic, raised, ulcerative mass on the lateral aspect of the left thigh. Histopathology of an excisional biopsy revealed severe, chronic, multifocal-to-coalescing, ulcerated dermal and subcutaneous granulomas. No infectious organisms were observed on Ziehl-Neelsen or Gomori methenamine silver stains. The parrot was treated with oral sulfamethoxazoletrimethoprim and meloxicam. When reexamined 2 weeks later, the biopsy site had healed. Surgical biopsies were resubmitted 14 months after the original presentation due to recurrence of similar ulcerative lesions on the right leg. Histopathology revealed a similar inflammatory pattern, and hematoxylin-eosin, Ziehl-Neelsen, and silver stains on the biopsy samples were all negative. A Fite-Faraco stain revealed rare acid-fast bacilli throughout the lesion. Tissue polymerase chain reaction test was negative for Mycobacterium avium and Mycobacterium genavense. Mycobacterial culture and subsequent genotyping revealed Mycobacterium kansasii. Mycobacterium kansasii is a significant cause of mycobacteriosis in humans and, therefore, should be considered a potential zoonotic organism. This report describes an unusual primary cutaneous presentation of avian mycobacteriosis.

Clinical Performance of Mycobacterial Immunohistochemistry in Anatomic Pathology Specimens.

OBJECTIVES: Diagnosis of mycobacterial infections poses significant challenges in anatomic pathology. We recently described the use of antimycobacteria immunohistochemistry (IHC) as a sensitive, efficient diagnostic tool and now report the clinical performance of this assay among general, noninfectious disease pathology-trained anatomic pathologists. METHODS: Over a 2-year period, all cases were retrospectively identified in which mycobacterial IHC was performed during routine diagnostic workup. RESULTS: From October 2017 to September 2019, mycobacterial IHC was evaluated for 267 cases, resulting in 58 (22%) positive stains. Compared with culture and molecular results, the sensitivity and specificity of IHC were 52% and 80%, respectively. IHC performed significantly better than acid-fast bacilli (AFB) staining (Ziehl-Neelsen) (P < .0001; sensitivity 21%, specificity 92%) but similarly to modified AFB staining (mAFB; Fite-Faraco) (P = .9; sensitivity 61%, specificity 84%). In cases with discordant IHC and mAFB staining, there were no differences in rates of culture or polymerase chain reaction-confirmed positivity. CONCLUSIONS: Mycobacterial IHC was well adopted with superior clinical performance to AFB and comparable performance to mAFB. These results support the use of IHC as an adjunctive tool in the diagnosis of mycobacterial infections and suggests its potential role as a rapid screening test for molecular testing.

Clinico-Histological Correlation in Hansen's Disease: Three-year Experience at a Newly Established Tertiary Care Center in Central India.

BACKGROUND: Hansen's disease is a chronic infectious disease caused by Mycobacterium leprae. It is characterized by a wide range of clinical and histological manifestations. Ridley-Jopling criteria are widely used for classifying leprosy. The demonstration of acid-fast bacilli on slit-skin smear examination and in skin biopsy aids in its diagnosis. AIM: The aim of the present study was to perform clinico-histological correlation of skin lesions in all patients with a clinical suspicion of Hansen's disease. MATERIALS AND METHODS: The study included skin biopsies of all suspected cases of Hansen's disease received over a period of 3 years. Hematoxylin and eosin and Fite-Faraco stained sections of all cases were examined. Corresponding slit-skin smears, if available, were also reviewed. RESULTS: During the study, a total of 116 cases were clinically diagnosed as Hansen's disease. Clinico-histological correlation was obtained in 62.9% of the cases (73/116). The most common histological subtype of Hansen's disease was borderline tuberculoid (TT) (40/116). Seven cases were diagnosed as lepromatous leprosy, five as TT, four as histoid, one as indeterminate, and three cases diagnosed as erythema nodosum leprosum. Fite-Faraco stain was positive in 33/73 cases. Out of 116 cases, slit-skin smears were available for 43 cases and were positive in 23 cases. CONCLUSION: Correlation between clinical, bacteriological, and morphological features is required for accurate classification of Hansen's disease. Clinical detection and morphological diagnosis of early lesions remain challenging, and the histological findings should always be interpreted in correlation with clinical findings.

Evaluation of Fluorescent Staining for Diagnosis of Leprosy and its Impact on Grading of the Disease: Comparison with Conventional Staining.

INTRODUCTION: Leprosy is a chronic infectious disease caused by Mycobacterium leprae (M. leprae). Histopathological examination of skin lesion is the gold standard for diagnosis. We evaluated the possible role of fluorescent microscopy in this direction which is increasingly used for rapid screening. AIM: To compare the efficacy of auramine rhodamine stain with Ziehl-Neelsen and modified Fite-faraco staining in diagnosing M. leprae in tissue sections. STUDY DESIGN: Experimental, cross-sectional and retrospective study conducted for 4 years. METHODS AND MATERIALS: Skin biopsies of sixty clinically diagnosed leprosy patients were stained by Ziehl-Neelsen, Fite-Faraco and fluorescent stain. The presence of the bacilli and the bacillary index was scored for each case. The bacillary index by each staining methods were compared. STATISTICAL ANALYSIS: SPSS v 17 (IBM, New York) used for data analysis. Chi-Square test was used to calculate significance between differences. The p-value of <0.05 was considered as statistically significant. Pearson Correlation (r-value determined) was also used for comparison between groups. RESULTS: Sensitivity of fluorescent stain for indeterminate and borderline tuberculoid leprosies were 100% each. Positivity rates and mean bacteriological index with fluorescent stain was higher (43.3 and 11.5 respectively) as compared to that of Ziehl- Neelsen and Fite-faraco when the bacillary load was less (bacillary index < 3). There was significant correlation between the three staining types at higher bacillary load. There was a higher mean bacillary index with fluorescent stain as well as detection of an additional multibacillary case. CONCLUSION: Fluorescent method is more sensitive than modified fite-faraco method in detecting lepra bacilli in tissue sections especially in cases with bacillary index less than three. With its higher sensitivity, paucibacillary cases could be upgraded to multibacillary thus affecting treatement decisions.