Pneumocystis carinii infection presenting as necrotizing thyroiditis and hypothyroidism

Area of Science:

• Infectious Diseases
• Endocrinology
• Oncology

Background:

• Extrapulmonary Pneumocystis infection is increasingly reported in individuals with acquired immune deficiency syndrome (AIDS).
• The use of aerosolized pentamidine for prophylaxis has been associated with emerging cases of extrapulmonary Pneumocystis.
• Patients with AIDS often present complex diagnostic challenges, particularly with unusual mass lesions.

Observation:

• A 37-year-old male with hemophilia and AIDS presented with an unusual thyroid neck mass and clinical hypothyroidism.
• This case involved a rapidly enlarging neck mass, unlike previously reported isolated thyroid pneumocystosis.
• The patient had no prior history of Pneumocystis infection and had received aerosolized pentamidine prophylaxis.

Findings:

• Pathologic and electron microscopic examination revealed flocculent necrotic thyroid material.
• Findings were contrasted with typical pulmonary findings in Pneumocystis pneumonia (PCP).
• Differential diagnoses for a rapidly expanding neck mass and hypothyroidism in AIDS patients were discussed.

Implications:

• Aerosolized pentamidine, while effective for pulmonary PCP prevention, may be insufficient for preventing extrapulmonary Pneumocystis infections.
• This case underscores the need to consider extrapulmonary Pneumocystis in the differential diagnosis of neck masses in AIDS patients.
• Diagnostic strategies for hypothyroidism in immunocompromised patients require careful consideration of opportunistic infections.