Non-Infectious Granulomatous Dermatoses

Abstract

Granulomatous dermatitis (GD) is one of the commonest tissue reaction patterns encountered in dermatopathology practice. Granulomatous inflammation in the skin can be seen in a wide range of conditions, thus, granulomatous dermatitis always poses significant challenge even to the astute dermatologists and dermatopathologists. Broadly, granulomatous dermatitis is divided into two groups—infectious and non-infectious, the prevalence of both highly variable and show overlapping pathology. However, there are subtle histological clues, which when combined with clinical features, help to narrow down the differential diagnosis. Thus, a good Clinicopathological correlation (CPC) along with histochemical stains, culture and ancillary techniques including molecular studies are required for arriving at a definite diagnosis. In this review, we shall discuss the histological clues to diagnose non-infectious granulomatous dermatitis (NIGD) and their differential diagnoses.

Loss of Eyebrow Hair and Pigment: Case Challenge: Answer

“…Lepromatous leprosy would stain positive for micro-organisms with a modified Ziehl–Neelsen stain (Wade-Fite) stain. 8 Vitiligo would reveal striking depigmentation of established and developed lesions with Wood's lamp (wavelengths in the 320- to 450-nm range) not the mild hypopigmentation noted in our patient. On histology, vitiligo is characterized by absence of melanocytes.…”

Radiotherapy for aseptic granulomatous dermatitis: A case report

“…Concerning types of granulomatous dermatitis that may be seen in America, there are quite a few including tuberculoid granuloma, suppurative granuloma, interstitial granuloma, and sarcoidal granuloma among a few others. 1 …”

Rubella virus‐associated necrotizing neutrophilic granuloma in a patient with common variable immunodeficiency

“…In a patient with IEI, the clinical differential diagnosis of scaly, erythematous to violaceous, ulcerated papules and plaques include non‐infectious granulomas, 2,3 infection, and malignancy. The histopathologic differential diagnosis of necrotizing neutrophilic and palisaded granulomatous inflammation from lesions confined to the lower leg includes infection which requires correlation with special stains, tissue cultures, and molecular studies for organisms including bacteria, fungus, and mycobacteria; necrobiosis lipoidica, which shows palisaded histiocytes and epithelioid granulomas without significant neutrophils and associated with necrobiotic collagen arranged in a layered manner; and cutaneous sarcoidosis which in a minority of cases may show central caseation necrosis surrounded by epithelioid histiocytes rather than the more typical epithelioid granuloma without central necrosis and devoid of significant inflammation 10 …”