Type II pleuropulmonary blastoma mistaken for rhabdomyosarcoma: A case report

Abstract

Introduction: Pleuropulmonary blastoma (PPB) is rare, representing 0.3 % of all pediatric cancers. PPB is classified into three subtypes and may progress from type I to types II and III, with a worse prognosis. Given its rarity, the diagnosis is frequently challenging.

Case presentation: We report an occurrence of PPB in a 3-year-old girl, who presented recurrent pneumopathy. Imaging investigations revealed a large solid lesion in the left hemithorax. Biopsy followed by histological analysis suggested rhabdomyosarcoma. The patient received neoadjuvant chemotherapy before proceeding to complete tumor excision. Surgical exploration revealed that the tumor was primitively related to parietal pleura and lower lobe of left lung. Histopathology of the tumor retained a definitive diagnosis of PPB type II. Postoperative course was uneventful, and a cerebral MRI ruled out brain metastasis. Adjuvant chemotherapy was administered.

Discussion: Clinical expression of PPB is nonspecific and variable. It ranges from a dry cough to respiratory distress. Standard radiography is the first examination to perform and CT is the gold standard for characterization thoracic masses. Surgery and chemotherapy are the pillars of treatment. Indications depend on the tumor type, its extent and its resectability.

Conclusion: PPB is an aggressive tumor that occurs only in children. Due to the rarity of PPB, evidence on optimal treatment is still insufficient. Careful follow-up is necessary searching for local recurrence or metastasis.

Keywords: Case report; Pediatric neoplasms; Pleuropulmonary blastoma; Pneumoblastoma; Rhabdomyosarcoma; Thoracic neoplasm.

Fig. 1

Chest Radiograph showing a radio-opaque mass lesion occupying the left hemithorax with controlatéral mediastinal deviation.

Fig. 2

A - Axial chest CT mediastinal window with contrast enhancement. B - Coronal chest CT mediastinal window with contrast enhancement. C - Sagittal chest CT mediastinal window with contrast enhancement. Large well defined solid mass with heterogeneous enhancement occupying almost the totality of the left hemi-thorax with controlateral mediastinum deviation and no evidence of parietal invasion. The Sagittal reformed image shows the associated pleural effusion.

Fig. 3

Chest CT after 4 cycles of neoadjuvant chemotherapy IVA. A- Axial chest CT mediastinal window with contrast enhancement. B- Axial chest CT Lung window. C- Sagittal chest CT Lung window. Decrease in size of the left pleural-pulmonary tissue mass with secondary appearance of excavations with aerated content.

Fig. 4

A/ Gross examination of a type II pleuropulmonary blastoma presenting as a solid-cystic lesion in the lung of a 3-year-old girl; B/ Type II pleuropulmonary blastoma tumor composed of cystic and solid components (H&E ×200): The cystic component (asterix) is composed of cysts separated by fibrous septa of varying thickness and lined by alveolar-type epithelium. Beneath this lining, there was a condensation of immature mesenchymal cells, often associated with varying numbers of rhabdomyoblasts (head arrow). The solid component consisted of a mixture of blastemal and sarcomatous foci. The sarcomatous component was of rhabdomyosarcomatous and chondrosarcomatous types (arrow).

Fig. 5

Post-tumorectomy chest CT control. A- Axial chest CT mediastinal window with contrast enhancement. B- Axial chest CT Lung window. C- Sagittal chest CT Lung window. No evidence of tumor residue and complete regression of the pleural effusion.