ABSTRACT
Introduction@#Cutaneous protothecosis usually presents as pyoderma-like lesions or infiltrating papules and plaques on the extensor side of the extremities. It can be misdiagnosed as eczema, pyoderma, or a fungal infection. Although it has been isolated from a swimming pool, sewers and rivers in the Philippines, there has been no reported case of cutaneous protothecosis in the country.@*Case summary@#A 78-year-old Taiwanese male farmer visited the dermatology clinic due to a six-month history of a large, pruritic erythematous plaque studded with papulopustules on his left forearm. A potassium hydroxide (KOH) examination showed negative for hyphae or spores. And a skin biopsy showed morula-like bodies, which were highlighted by the Periodic acid-Schiff stain.@*Conclusion@#We report a case of cutaneous protothecosis from Taiwan so Filipino dermatologists will be aware of the clinical and histopathologic manifestations and management of cutaneous protothecosis.