Argyria an unrecognized cause of cutaneous pigmentation in Indian patients: A case series and review of the literature.

Argyria is an uncommon grey-blue pigmentation of skin and mucous membranes caused by prolonged silver exposure. The impetus behind this review is our experience with cases of generalized argyria resulting from a uniquely Indian socio-cultural practice and belief that it is under reported. Our objective is to increase the awareness for this esoteric entity through a review of the pertinent literature and to highlight clinical and histological features using our four well worked-up cases as examples.

Clinicopathological correlation of acquired hypopigmentary disorders.

Acquired hypopigmentary disorders comprise a significant group of disorders that affect Indians and Asians. The pigment disturbance in darker skin individuals can be very distressing to the patient and the family. These disorders cover a wide array of pathologies including infections, autoimmune processes, lymphoproliferative disorders, and sclerosing diseases. Histological diagnosis is particularly important because treatments for these diseases are varied and specific. This review will focus on histopathological diagnosis based on clinicopathological correlation for commonly encountered disorders such as leprosy, vitiligo, lichen sclerosus, pityriasis alba (PA), and pityriasis versicolor (PV). Atypical or uncommon clinical presentation of classic diseases such as hypopigmented mycosis fungoides (HMF) and hypopigmented sarcoidosis are also included.

Clinicopathological correlation of acquired hyperpigmentary disorders.

Acquired pigmentary disorders are group of heterogenous entities that share single, most significant, clinical feature, that is, dyspigmentation. Asians and Indians, in particular, are mostly affected. Although the classic morphologies and common treatment options of these conditions have been reviewed in the global dermatology literature, the value of histpathological evaluation has not been thoroughly explored. The importance of accurate diagnosis is emphasized here as the underlying diseases have varying etiologies that need to be addressed in order to effectively treat the dyspigmentation. In this review, we describe and discuss the utility of histology in the diagnostic work of hyperpigmentary disorders, and how, in many cases, it can lead to targeted and more effective therapy. We focus on the most common acquired pigmentary disorders seen in Indian patients as well as a few uncommon diseases with distinctive histological traits. Facial melanoses, including mimickers of melasma, are thoroughly explored. These diseases include lichen planus pigmentosus, discoid lupus erythematosus, drug-induced melanoses, hyperpigmentation due to exogenous substances, acanthosis nigricans, and macular amyloidosis.

Porokeratotic eccrine ostial and dermal duct nevus.

Porokeratotic eccrine ostial and dermal duct nevus (PEODDN) is a rare variant of porokeratosis with characteristic histological feature of cornoid lamella involving the acrosyringium. We report a classic case of a 20-year-old male, who clinically presented to us with keratotic papules and plaque with pits, few having comedo like plugs, on right palm and sole since 1 year of age. A punch biopsy from palm was diagnostic as well as confirmatory showing cornoid lamella involving an eccrine duct which is the characteristic histopathological feature of PEODDN.