Intrapulmonary thymoma

Definition

A tumour identical to mediastinal thymoma but arising within the lung, without mediastinal involvement2. See also pleural thymoma.

Epidemiology

The median age is 50 years, possibly with a female predominance2.

Clinical features

Rarely, myasthenia gravis may occur.

Radiology

The tumour may be central or peripheral2. Rarely, there are multiple masses2.

Macroscopic appearances

The tumour is usually lobulated, circumscribed and encapsulated. There may be cyst formation.

Histopathology

As for the range of mediastinal thymoma. Perivascular spaces may be prominent2.

Immunohistochemistry

As for the range of mediastinal thymoma, including the presence of immature lymphocytes1.

Differential diagnosis

• Primary mediastinal thymoma.

• Carcinoma: show cytological malignancy.

• Carcinoid

• Lymphoma: lack an epithelial component.

• Small cell carcinoma: show cytological malignancy.

Management

Surgical resection. Nodal involvement has been described and requires nodal resection.

Prognosis

Good2.

References

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

1 Fukayama M, Maeda Y, Funata N, et al. Pulmonary and pleural thymoma. Diagnostic application of lymphocyte markers to the thymoma of unusual site. Am J Clin Pathol 1988; 89:617-21

2 Moran CA, Suster S, Fishback NF, et al. Primary intrapulmonary thymoma. A clinicopathologic and immunohistochemical study of eight cases. Am J Surg Pathol 1995; 19:304-12

This page last revised 20.6.2005.

©SMUHT/PW Bishop