CHEST Guidelines-An-Unusual-Cause-of-Pulmonary-Nodules-After-Stem-C

An-Unusual-Cause-of-Pulmonary-Nodules-After-Stem-C

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The case study discusses a man in his 20s with a history of classical Hodgkin’s lymphoma, presenting with fever after undergoing both autologous and allogeneic stem cell transplants. A surveillance CT scan revealed the resolution of his original mediastinal mass, but it also detected numerous new pulmonary nodules. Despite treatment with antimicrobials for suspected infection, his condition persisted, leading to further investigation by transthoracic biopsy.<br /><br />Histological examination showed features indicating classical Hodgkin’s lymphoma, with findings such as large cells expressing CD30 without CD20 staining. The radiologic pattern, smooth-bordered nodules concentrated in the lung periphery with feeding vessels, was unusual for typical Hodgkin lymphoma presentation in the lungs. This prompted the consideration of the potential hematogenous spread of residual tumor cells (RTCs) during autologous stem cell transplantation.<br /><br />The case highlights various potential causes of pulmonary nodules in the context of stem cell transplantation, distinguishing between infectious and noninfectious causes. While initial consideration is often given to infections, especially in the early post-engraftment period, opportunistic pathogens like molds, endemic mycoses, and certain bacterial infections are typical suspects. In this patient, noninfectious explanations, such as malignancy, had to be considered due to the nodules' persistence despite broad-spectrum antimicrobial treatment.<br /><br />Critical learning points include recognizing that relapsed Hodgkin’s lymphoma can present with pulmonary nodules and understanding that stem cell transplantation may inadvertently mobilize tumor cells, leading to relapse. Proper diagnostic strategies are essential, often requiring a biopsy to differentiate between infectious and malignant causes, factoring in both clinical context and procedural risks like pneumothorax. The case emphasizes the need for careful differential diagnosis in post-transplant patients with pulmonary manifestations.

Keywords

Hodgkin's lymphoma

pulmonary nodules

stem cell transplantation

autologous transplant

allogeneic transplant

transthoracic biopsy

CD30 expression

hematogenous spread

noninfectious causes

differential diagnosis