Prototheca species are ubiquitous, aerobic, unicellular algae closely related to the green algae Chlorella. Their involvement in human disease--in both immunocompetent and immunocompromised patients--has been reported with increasing frequency. The wide array of presentations has included cutaneous, subcutaneous, mucosal, bursal, catheter-related, and (in rare instances) systemic disease. We report a case of protothecosis complicating prolonged endotracheal intubation presenting as a nasopharyngeal ulceration with a soft-tissue mass, and we review the presentation, treatment, and outcome of the 59 previously reported cases of protothecosis. Optimal therapy for protothecosis includes excision (where possible) followed by systemic administration of amphotericin B; the sole exception is in the case of olecranon bursitis, where excision alone appears curative. The role of the newer imidazoles is yet to be determined.