Discussion
Diagnosis With Brief Discussion
- Diagnosis
- Multifocal micronodular pneumocyte hyperplasia (MMPH) and lymphangioleiomyomatosis in patient with tuberous sclerosis
- Radiologic Findings
- Chest radiograph demonstrates diffuse, ill-defined, nodular opacities in both lungs. Computed tomography of the chest shows sharply and poorly defined small nodules, varying in diameter from 1 to 5 mm, and smooth thin-walled cysts diffusely scattered in both lungs.
- Brief Review
- MMPH is a rare benign hamartomatous proliferation of type II pneumocytes, often associated with tuberous sclerosis complex (TSC) and/or lymphangioleiomyomatosis (LAM). Most patients with MMPH in TSC are associated with LAM. Tuberin, the TSC2 gene product, has been recently found to be expressed in LAM and MMPH. The diagnosis of MMPH is confirmed by pathology, which will show proliferation of type II pneumocytes without the typical nuclear atypia and aggregations of macrophages in the alveolar lumens.
Characteristic CT features of MMPH are multiple tiny nodules (1-8 mm in diameter), which are diffusely scattered in a random distribution. Differential diagnoses include multiple atypical adenomatous hyperplasia, early pulmonary Langerhans cell histiocytosis, minute hematogeneous lung metastases, and miliary tuberculosis.
- References
- 1. Shigeaki Umeoka, Takashi Koyama, Yukio Miki, Mikio Akai, Kazushige Tsutsui, Kaori Togashi, Pictorial Review of Tuberous Sclerosis in Various Organs. Radiographics 2008; 28:e32
2. Maruyama H, Ohbayashi C, Hino O, Tsutsumi M, Konishi Y. Pathogenesis of multifocal micronodular pneumocyte hyperplasia and lymphangioleiomyomatosis in tuberous sclerosis and association with tuberous sclerosis genes TSC1 and TSC2. Pathol Int 2001; 51: 585–94.
3. Ristagno RL, Biddinger PW, Pina EM, Meyer CA. Multifocal micronodular pneumocyte hyperplasia in tuberous sclerosis. AJR Am J Roentgenol. 2005;184:S37-S39.
- Keywords
- Lung, Interstitial lung disease, ILD,