Desmoid tumour of the pleura

Epidemiology

Adults, over a wide age range.

Clinical features

In some cases there is a history of preceding trauma to the site. Most extra-abdominal desmoids of the chest present as palpable extra-thoracic masses; the diagnostic confusion with solitary fibrous tumour occurs when the desmoid is pleural-based.

Radiology

CT shows a pleural-based lesion with rounded contours and sharply defined borders. Calcification is not a feature.

Macroscopic appearances

Unlike solitary fibrous tumour, desmoids are not pedunculated but have a broad base of attachment to the pleura. Most are attached to the parietal pleura, a few to the pulmonary visceral pleura.

Histopathology

The keloid-like ropy collagen seen in solitary fibrous tumour is lacking. The collagen is more fibrillar, often with a loose myxoid character. Prominent inflammatory cell infiltrate and calcification are not a feature and would favour calcifying fibrous pseudotumour.

Immunohistochemistry¹

case	vimentin	SMA	muscle-specific actin	desmin	S-100	CD34	cytokeratin
1	+	+	+	focal	-	-	-
2	-	-	-	-	-	-	-
3	+	+	+	focal	-	-	-
4	+	+	+	focal	-	-	-

Differential diagnosis

• solitary fibrous tumour

• calcifying fibrous pseudotumour of the pleura.

• neurofibroma

• ganglioneuroma, if there are entrapped sympathetic ganglia within the desmoid.

Management

Treatment is by wide excision en bloc. They respond to antioestrogens (tamoxifen), nonsteroidal antiinflammatory drugs and radiotherapy.

Prognosis

Desmoids commonly recur if not excised with a margin of 3 to 4 cm with at least one unaffected rib above and below. They have no metastatic potential.

References

Kaplan J., Davidson T. Intrathoracic desmoids: report of two cases. Thorax 1986;41:894-5.

¹Wilson R.W., Gallateau-Salle F., Moran, C. A. Desmoid tumors of the pleura: a clinicopathologic mimic of localized fibrous tumor. Mod Pathol 1999;12:9-14

This page last revised 21.12.2000.

©SMUHT/PW Bishop