Congenital peribronchial myofibroblastic tumour5

Definition

A proliferation of uniform plump spindle cells in a peribronchovascular distribution.

Synonyms

Congenital fibrosarcoma4, congenital leiomyosarcoma, congenital mesenchymal malformation of the lung, neonatal pulmonary hamartoma.

Epidemiology

Less than 15 cases have been reported. There is no genetic predisposition or association with any syndrome.

Clinical features

The tumour presents during pregnancy with polyhydramnios / hydrops fetalis3,5, or shortly after birth.

Radiology

There is often an opaque hemithorax1.

Macroscopic appearances

The tumour is well demarcated but not encapsulated. The cut surface is fleshy and may show haemorrhage or necrosis. The tumour obliterates or distorts the bronchus.

Histopathology

Uniform spindle cells form intersecting fascicles1. Nuclei lack pleomorphism but mitotic activity is variable. The tumour may extend onto the pleural surface.

Immunohistochemistry

	Vimentin	positive0
	Desmin	negative or isolated cells0
	SMA	negative or isolated cells0
	Muscle specific actin	<5% of cells0

Ultrastructure

There are features of myofibroblastic differentiation.

Cytogenetics

Although the tumour resembles congenital infantile fibrosarcoma and congenital mesoblastic nephroma, there have been no reports of t(12;15)(p13;q25-26).

Differential diagnosis

Congenital infantile fibrosarcoma2

Management

The involved lobe or lung requires resection.

Prognosis

Fetal hydrops may be fatal but the behaviour of the tumour is benign1,4.

References

0 Tumours of the Lung, Pleura, Thymus and Heart. WHO Classification of Tumours. IARC Press 2004.

1 Alobeid B, Beneck D, Sreekantaiah C, et al. Congenital pulmonary myofibroblastic tumor: a case report with cytogenetic analysis and review of the literature. Am J Surg Pathol 1997; 21:610-4

2 Coffin CM, Jaszcz W, O'Shea PA, et al. So-called congenital-infantile fibrosarcoma: does it exist and what is it? Pediatr Pathol 1994; 14:133-50

3 Khong TY,Keeling JW. Massive congenital mesenchymal malformation of the lung: another cause of non-immune hydrops. Histopathology 1990; 16:609-11

4 Kuhnen C, Harms D, Niessen KH, et al. [Congenital pulmonary fibrosarcoma. Differential diagnosis of infantile pulmonary spindle cell tumors]. Pathologe 2001; 22:151-6

5 McGinnis M, Jacobs G, el-Naggar A, et al. Congenital peribronchial myofibroblastic tumor (so-called "congenital leiomyosarcoma"). A distinct neonatal lung lesion associated with nonimmune hydrops fetalis. Mod Pathol 1993; 6:487-92

This page last revised 5.5.2005.

©SMUHT/PW Bishop