INTRODUCTION: Granulomatous Pneumocystis carinii pneumonia is a rare subset of PCP in non-HIV patients.We present a rare case of granulomatous PCP,diagnosed on lung biopsy and did well with treatment.
CASE PRESENTATION: A 63-year-old woman who underwent an autologus bone marrow transplant 4 months back for multiple myeloma was admitted to the hospital for cough, rhinorrhea and a new right upper lobe pulmonary nodule. She denied other symptoms. She gave a past medical history of parainfluenza pneumonia, coagulase negative staphylococcus bactremia and hypertension. She had a 30 pack year smoking history but quit smoking five years back. Her medications were Valtrex, Triamterene, Leucovorin, Oxypamidronate and multivitaminsOn examination: Vital signs were normal and pulse oximetry was 98%.Her physical examination was normal. Her laboratory findings were all normal including CBC, Basic chemistry and lactate dehydrogenase.Blood culture and sputum culture were all negative. Chest radiograph and CT scan (Figure 1) showed a 1.5 X 1.1cm right upper lobe noduleShe was empirically started on antibiotics. Flexible bronchoscopy was performed. Broncho-alveolar lavage (BAL) demonstrated only alveolar macrophages and microscopic examination with appropriate stains and cultures for microbes were negative including Pneumocystis carinii pneumonia (PCP) direct fluorescence antibody (DFA) test. She underwent video-assisted thoracoscopic surgery (VATS) and lung biopsy. Histopathology showed several granulomas with central necrosis (fig. 2A and 2B).The AFB stains were negative. What is your diagnosis?.
DISCUSSIONS: Diagnosis: Granulomatous Pneumocystis carinii pneumoniaPneumocystis carinii pneumonia (renamed Pneumocystis jiroveci pneumonia) is a life-threatening opportunistic infection in immunosuppressed persons. PCP is increasingly recognized in HIV seronegative immunosuppressed transplant recipients and in patients undergoing treatment for hematological malignancies, collagen-vascular disorders and Wegener's granulomatosis with corticosteroids and /or chemotherapeutic agents (1). Long course corticosteroid treatment by in itself increases the risk of infection.Granulomatous Pneumocystis carinii pneumonia is a rare subset of PCP. In HIV infected patients with PCP the incidence of this subset is 5 % and lesser in non-HIV patients. Bondoc and White found only 3 cases of granulomatous PCP among all cases of PCP in HIV seronegative patients with malignancy, at a large tertiary cancer center over a 12-year period (1). These authors and others have pointed out several features of granulomatous PCP that make it difficult to diagnose. The onset of illness was insidious in these cases with mild cough or dyspnea with variable fever. Nodular or reticulonodular infiltrates were seen on chest radiography and the serum lactate dehydrogenase (LDH) values were normal or only slightly raised. Bronchoscopy, broncho-alveolar lavage (BAL) and transbronchial biopsy were nondiagnostic and open lung biopsy was necessary for diagnosis.The histological appearance of granulomatous PCP varies from an ill-defined granulomatous pneumonia to a well-formed necrotizing granuloma containing PCP. The typical intra-alveolar eosinophilic frothy exudate associated with PCP is absent.PCP is readily stained with Gomori methenamine-silver (GMS) and immunohistochemical stains. However appropriate histochemical stains and microbiological cultures are needed to rule out tuberculosis and fungal infections especially Histoplasma capsulatum, which typically shows a granulomatous pattern. Pneumocystis carinii and Histoplasma capsulatum organisms are similar in size, shape and staining characteristics. Treatment of granulomatous PCP is same as the usual form of PCP (1). Trimethoprim–sulfamethoxazole (TMP-SMZ) is very effective in both treating and preventing pneumocystis pneumonia.Our patient had adverse reactions to TMP-SMZ previously, so she was treated with Atovaquone , continued on prophylaxis and did well without any PCP recurrence in two months follow up.
CONCLUSION: In conclusion, awareness of various features of granulomatous PCP, as exemplified in our case, is important for early diagnosis and successful treatment of this potentially lethal infection.
DISCLOSURE: Manish Joshi, None.