Pulmonary sclerosing pneumocytoma: beyond the solitary nodule in childhood

Clinical History

A 5-year-old boy presented to the emergency department with dysphagia to solid food after choking. He had no history of dyspnoea or cyanosis. Physical examination and blood tests were normal. Chest radiography was performed where a pulmonary nodule was found incidentally. A thorax CT was requested to complete the study of this patient.

Imaging Findings

Posteroanterior chest radiography: Incidental, well-defined pulmonary nodule located in the right upper lobe (arrow in Fig. 1).
Thorax CT with intravenous contrast confirmed the existence of a well-defined pulmonary nodule located in the upper right lobe (Fig. 2 and 3). It showed high density in enhanced CT (Fig. 3) and an area of air-trapping in the adjacent pulmonary parenchyma (arrow in Fig. 2).
Despite the age, the clinical situation (normal physical examination and normal blood test) suggests the diagnosis of a tumour and not an infectious disease. In childhood the radiological characteristics of solitary pulmonary nodules are not enough to decide if they are benign or malignant, so a biopsy of this nodule was performed.
Pathological anatomy results revealed a pulmonary sclerosing haemangioma (pneumocytoma) (Fig. 4). It is a benign tumour, more frequent in adults.

Discussion

The radiological and tomographic findings of lung tumours are not specific in most cases. For these reasons, they constitute a great diagnostic challenge. [1]
Pulmonary masses are less frequent than mediastinal masses in children. Most of them are non-neoplastic congenital or inflammatory lesions. Furthermore, neoplastic lesions are more frequently malignant. [2]
In our case, the clinical situation (normal physical examination and normal blood test) exclude an inflammatory-infectious disease. Although radiological findings of pulmonary nodules are not specific, in this patient the existence of a well-defined nodule with homogeneous enhancement suggests a benign neoplasm.
The spectrum of benign lesions includes inflammatory myofibroblastic tumours, hamartomas and sclerosing haemangiomas (pneumocytomas), as well as nodular lymphoid hyperplasia and lymphoproliferative syndromes [3].
Pulmonary sclerosing haemangioma or pneumocytoma is a rare benign neoplasm which is more frequent in adults and women. Usually, patients who have this kind of tumour are asymptomatic. The diagnosis is confirmed by histology. Nevertheless, radiological features are very helpful to approach the diagnosis of this entity. In chest radiographs and thorax CT, it presents as a well-defined, solitary nodule with homogeneous enhancement after administration of intravenous contrast [4]. Sometimes, it can be associated with an air-trapping area in the periphery of the nodule (“air meniscus sign”) (Fig. 2). This sign is better seen in thorax CT. Despite being rare, it is very useful to differentiate this neoplasm from others like inflammatory myofibroblastic tumour. [4] On MR, pneumocytoma is hyperintense on T1-weighted and T2-weighted sequences. Sometimes, it can present cysts o haemorrhage areas. In childhood, MR is the technique of choice to complete the characterisation of a solitary pulmonary nodule because of the absence of radiation. However, in our case, a CT was performed because the diagnosis was made during the emergency shift.
Surgical excision is the treatment of choice, which was also performed in the case presented.

Differential Diagnosis List

Final Diagnosis

Pulmonary sclerosing haemangioma or pneumocytoma

URL:	https://eurorad.org/case/15425
DOI:	10.1594/EURORAD/CASE.15425
ISSN:	1563-4086