A Case of Cutaneous Protothecosis in an Immunocompetent Patient

Annular infectious dermatoses

Annular configuration is conspicuous in the clinical manifestation of many skin diseases and can be helpful for the diagnosis and differential diagnosis. Variations may include arciform, ring-form, annular, circinate, serpiginous, gyrated, polycyclic, targeted or figurate forms, in different colors, sizes, and numbers, with various textures and surfaces. In infectious dermatoses, the annular reactions can be specific or nonspecific, while the underlying mechanisms remain largely unknown. In the specific reactions caused by direct invasion of the pathogens, the contest between the centrifugal outspread of the infectious agents and the centripetal impedance of the host immune response is supposed to determine the final conformation. Examples include erythema infectiosum, orf, erythema multiforme, and pityriasis rosea of viral origin. Bacterial infections that may display annular lesions include erythrasma, erythema (chronicum) migrans of Lyme borreliosis, secondary syphilis, cutaneous tuberculosis, and leprosy. Superficial mycosis, such as dermatophytosis, candida intertrigo, tinea imbricata, and subcutaneous mycosis, such as chromoblastomycosis, and algae infection protothecosis, are characterized by annular progression of the skin lesions. The creeping serpiginous extension is an alarming sign for the diagnosis of cutaneous larva migrans. A better understanding of the virulence and pathogenicity of the pathogens and the way and type of immune response will help to clarify the pathogenesis.

Cutaneous Protothecosis as an Unusual Complication Following Dermal Filler Injection: A Case Report

A 77-year-old female patient presented with bilateral tender, swollen, erythematous, focally crusted cheeks with a discharge of pus and necrotic material, which had developed one month after autologous fat transfer and a corrective injection procedure conducted to correct an overdone fat transfer. Histopathological examination of the discharged material using routine hematoxylin and eosin staining revealed degenerated collagen admixed with three different filler materials. Scattered all throughout the specimen were numerous thick-walled, basophilic, nonbudding spherical bodies of variable sizes. The bodies stained positively with Periodic acid-Schiff and Alcian blue and showed internal septation and sporangia with a morula-like appearance. The morphology of these bodies was characteristic of a Prototheca infection. The patient was treated by surgical drainage accompanied by itraconazole 200mg daily for six months, ultimately showing marked improvement.