Vulval Tuberculosis: The Histomorphological Spectrum in Patients with HIV Co-Infection and AIDS

Abstract

Objective: Vulval tuberculosis (TB) is reported rarely. The histomorphological spectrum and diagnostic mimicry thereof in patients with concomitant HIV infection/ AIDS is unreported to date. This study aimed to appraise the histopathologic spectrum of vulval TB in HIV co-infected patients and to identify histopathological diagnostic challenges, mimicry and pitfalls. Methods: Ten year retrospective study that reappraised the histomorphological features of vulval TB in HIV-infected patients. Results: The clinical descriptions of the biopsied lesions from 19 patients that form the study cohort encompassed nodules (9), ulcers (5), hypertrophy/edema (3) and abscesses (2). The main microscopic features included necrotizing and non-necrotizing granulomatous inflammation, ulceration with a zoned inflammatory response and chronic suppurative inflammation. The necrotizing component had the typical morphology of caseative necrosis or of suppuration/karyorrhexis or an admixture of both necrosis types. Vasculitis, of varied histomorphology, was present in 15 biopsies. Infective special stains were pivotal diagnostic tools. The presence of mycobacteria on Ziehl Neelsen stains (ZNs) and absence of nonmycobacterial infective agents on additional infective stains, underpinned TB diagnosis, especially in biopsies that lacked prototypical granulomatous inflammation or of infective mimickers that manifest with a granulomatous phenotype. ZNs also confirmed mycobacteria in vasculitic foci. The absence of mycobacteria on ZNs facilitated the diagnosis of tuberculids. Conclusion: Lesions with a common clinical appearance had heterogeneous histomorphological features, while lesions with common histopathological features demonstrated divergent clinical morphology. Infective, especially Ziehl Neelsen, stains are pivotal in the histopathological work-up of infective/inflammatory vulval biopsies. It is possible that the rarely reported anergic mononuclear or abscessing features, pseudotumoral spindle cell reactions, ulcers with a zoned inflammatory response and the presence of vasculitis of varied type, are clues to the HIV-TB tissue partnership. Increased clinicopathological investigation of and reporting on vulval TB in the HIV/AIDS afflicted population is pivotal to ascertain this.