Pseudomembranous disease (or ligneous inflammation) is a rare condition characterized by accumulations of fibrin-rich eosinophilic material. Recent investigations have linked the etiology of this condition to plasminogen deficiency (hypoplasminogenemia). Although much of the literature concerning this disease has focused upon the often clinically striking ocular manifestations, it is important to note that pathologic changes may develop in a variety of anatomic locations, including the oral cavity, upper and lower respiratory tract, female genital tract, kidneys, and gastrointestinal tract. Here, we report an unusual case of a 33-year-old woman who initially presented with gingival inflammation. In subsequent years, she developed additional signs and symptoms related to sinonasal and genital tract involvement. Despite numerous clinical evaluations, biopsies, and laboratory tests, the patient's diagnosis remained elusive for 7 years. Ultimately, it was the distinctive appearance of the gingiva that led to a diagnosis of plasminogen deficiency. Unfortunately, the complicated clinical course and elapsed time between initial presentation and diagnosis illustrated by the present case are not uncommon among patients with this condition. Greater familiarity with the clinical and histopathologic features of this condition among pathologists and treating clinicians is essential for timely diagnosis and management.