A 45-year-old, men who have sex with men (MSM) patient with no significant, past medical history presented with the complaint of one week's duration of abdominal pain and fever of later onset (Day 1). The patient reported a weight loss of 10 kg over the past two months but denied respiratory symptoms, such as cough, dyspnea, and sputum, and asthenia. Physical examination revealed body temperature 37.9 C, heart rate 125 beats per minute, respiratory rate 20 breaths per minute, and oxygen saturation 95% on ambient air. Physical examination revealed normal lung sounds and no abdominal mass and tenderness. Laboratory tests revealed normal leucocytes (8200/muL) with lymphopenia (lymphocyte count 650/muL) and a low CD4 count (14/muL), anemia (hemoglobin 10.7 g/dL), thrombocytopenia (platelets 136,000/muL), hypoalbuminemia (albumin 2.7 g/dL), elevated lactate dehydrogenase (277 IU/L), C-reactive protein (29.41 mg/dL), serum beta-d-Glucan 127.6 pg/mL (positive >= 80 pg/mL), and 54,000 copies/mL of HIV viral load. Based on these findings, HIV infection was diagnosed. A chest x-ray and Chest computed tomography (CT) revealed multiple lung cysts, respectively (Fig. 1 (A), (B)). In addition, abdominal contrasted CT revealed multiple hypodense cystic lesions in the spleen (Fig. 2. (A), (B)). Pneumocystis jirovecii pneumonia (PCP)was diagnosed on the basis of chest CT findings and elevated beta-D-glucan, and a 21-day course of trimethoprim/sulfamethoxazole was administered (the trimethoprim component of 5 mg/kg per day was given three times daily). Initially, extrapulmonary tuberculosis and lymphoma were considered as the differential diagnosis of the splenic lesions. A QuantiFERON-TB Gold Plus test returned negative. An ultrasound-guided needle biopsy of the spleen was performed on Day 4, and histological analysis revealed infiltration of foamy macrophages without granulomatous inflammation and lymphoid cells (Fig. 3 (A)). Although gram staining and Auramine-rhodamine staining did not reveal any bacteria and acid-fast bacilli, respectively, Grocott's methenamine silver staining revealed spherical cysts compatible with P. jirovecii (Fig. 3. (B)). An immunofluorescence assay for P. jirovecii was also positive for the cysts (Fig. 3. (C)). Based on these findings, an extrapulmonary P. jirovecii infection of the spleen was diagnosed.(Fig. 4, Fig. 5).
The abdominal pain gradually resolved, and on Day 10, the fever resolved. On Day 11, antiretroviral therapy (ART) with tenofovir disoproxil fumarate/emtricitabine and dolutegravir were begun. Chest CT on Day 24 revealed a decrease in the number of lung cysts (Fig. 1. (H)). Abdominal contrasted CT performed on the same day revealed enlargement of the multiple cystic lesions in the spleen (Fig. 1. (I), (J)). On Day 25, the fever recurred. There was no onset of new symptoms, and laboratory tests revealed no new abnormalities. Blood cultures and mycobacterial blood cultures, which were done because bacteremia and disseminated Mycobacterium avium-complex infection were suspected, returned negative. IRIS associated with a splenic P. jirovecii infection was suspected because the splenic lesions had enlarged after the antiretroviral therapy was begun, no other cause of fever was able to be established definitively. A decision was made to carefully observe the recurrence of abdominal symptoms without resuming trimethoprim/sulfamethoxazole or starting any additional treatment. On Day 31, the fever resolved. Follow-up abdominal contrast CT on Day 36 revealed no change in the size of the splenic lesions from Day 24. Still, abdominal contrast CT on Day 61 demonstrated a decrease in the size of the lesions, and chest CT revealed nearly complete resolution of the lung cysts, confirming our suspicion of IRIS associated with a splenic P. jirovecii infection. The clinical course was not complicated with either splenic rupture or splenic bleeding. Follow-up was performed via regular clinic visits and monitoring clinical symptoms and laboratory data. No relapse of the splenic lesions was observed in the following, two years.
(B): Chest CT on Day 1 revealed multiple, diffuse lung cysts.