Multifocal micronodular pneumocyte hyperplasia explained

Multifocal micronodular pneumocyte hyperplasia (MMPH) is a subtype of pneumocytic hyperplasia (hyperplasia of pneumocytes lining pulmonary alveoli).^{[1] [2] [3] [4] [5]}

Several synonymous terms have been done for this entity: adenomatoid proliferation of alveolar epithelium, papillary alveolar hamartoma, multifocal alveolar hyperplasia, multinodular pneumocyte hyperplasia.

These multifocal lesions are observed in tuberous sclerosis,^{[6] [7]} and can be associated with lymphangioleiomyomatosis^[8] and perivascular epithelioid cell tumour (PEComa or clear cell "sugar tumor")).^[9]

It can be diagnosed through lung biopsy using thoracoscopy.^[10]

Microscopy

• Well-demarcated, nodular lesions ranging 2–5 mm in pulmonary parenchyma.
• Type II pneumocytes without nuclear atypia lined thickened alveolar septa and proliferated papillary structures.
• Enlarged cuboidal cells lining mildly thickened alveolar septa.^[11]
• Enlarged cuboidal cells have abundant, eosinophilic cytoplasm and large, round nuclei.^[12]
• Papillary pattern with irregular margin and lymphocyte infiltration in the stroma.^[13]
• No proliferation of immature smooth muscle cells suggestive of lymphangioleiomyomatosis.

See also

• atypical adenomatous hyperplasia
• pneumocytic hyperplasia

External links

• Microscopical images
• Microscopical images
• Microscopical images

Notes and References

1. 9537475. 1998. Muir. T. E.. Micronodular pneumocyte hyperplasia. The American Journal of Surgical Pathology. 22. 4. 465–72. Leslie. K. O.. Popper. H. Kitaichi. M. Gagné. E. Emelin. J. K.. Vinters. H. V.. Colby. T. V. . 10.1097/00000478-199804000-00012.
2. 23072249. 2012. Ishii. M. Tuberous sclerosis diagnosed by incidental computed tomography findings of multifocal micronodular pneumocyte hyperplasia: A case report. Journal of Medical Case Reports. 6. 1. 352. Asano. K. Kamiishi. N. Hayashi. Y. Arai. D. Haraguchi. M. Sugiura. H. Naoki. K. Tasaka. S. Soejima. K. Sayama. K. Betsuyaku. T. 10.1186/1752-1947-6-352. 3512476. free.
3. 22884294. 2013. Miravet Sorribes. L. Multifocal micronodular pneumocyte hyperplasia in a patient with tuberous sclerosis. Archivos de Bronconeumología. 49. 1. 36–7. Mancheño Franch. N. Batalla Bautista. L. 10.1016/j.arbres.2012.06.006.
4. 20190710. 2010. Shintani. Y. A case of micronodular pneumocyte hyperplasia diagnosed through surgical resection. Annals of Thoracic and Cardiovascular Surgery. 16. 1. 45–7. Ohta. M. Iwasaki. T. Ikeda. N. Tomita. E. Nagano. T. Kawahara. K.
5. 18535095. 2008. Kobashi. Y. Multifocal micronodular pneumocyte hyperplasia associated with tuberous sclerosis: Differentiation from multiple atypical adenomatous hyperplasia. Japanese Journal of Clinical Oncology. 38. 6. 451–4. Sugiu. T. Mouri. K. Irei. T. Nakata. M. Oka. M. 10.1093/jjco/hyn042. free.
6. 16595993. 2006. Kamiya. H. Tuberous sclerosis complex complicated by pulmonary multinodular shadows. Internal Medicine (Tokyo, Japan). 45. 5. 275–8. Shinoda. K. Kobayashi. N. Kudo. K. Nomura. T. Morita. T. Fujii. T . 10.2169/internalmedicine.45.1136. free.
7. 15942095. 2005. Kobashi. Y. Multifocal micronodular pneumocyte hyperplasia in a man with tuberous sclerosis. Internal Medicine (Tokyo, Japan). 44. 5. 462–6. Yoshida. K. Miyashita. N. Niki. Y. Matsushima. T. Irei. T . 10.2169/internalmedicine.44.462. free.
8. 11406664. 2001. Maruyama. H. Multifocal micronodular pneumocyte hyperplasia and lymphangioleiomyomatosis in tuberous sclerosis with a TSC2 gene. Modern Pathology. 14. 6. 609–14. Seyama. K. Sobajima. J. Kitamura. K. Sobajima. T. Fukuda. T. Hamada. K. Tsutsumi. M. Hino. O. Konishi. Y. 10.1038/modpathol.3880359. free.
9. 9331299. 1997. Flieder. D. B.. Clear cell "sugar" tumor of the lung: Association with lymphangioleiomyomatosis and multifocal micronodular pneumocyte hyperplasia in a patient with tuberous sclerosis. The American Journal of Surgical Pathology. 21. 10. 1242–7. Travis. W. D. . 10.1097/00000478-199710000-00017.
10. 12097776. 2002. Fujitaka. K. A case of micronodular pneumocyte hyperplasia diagnosed through lung biopsy using thoracoscopy. Respiration; International Review of Thoracic Diseases. 69. 3. 277–9. Isobe. T. Oguri. T. Yamasaki. M. Miyazaki. M. Kohno. N. Takeshima. Y. Inai. K . 10.1159/000063635. 38358651.
11. 24159404. 2013. Suzuki. K. Reversed halo sign in tuberous sclerosis complex. Case Reports in Radiology. 2013. 1–4. Seyama. K. Hayashi. T. Yamashiro. Y. Shiraishi. A. Kuwatsuru. R. 10.1155/2013/428501. 3789275. free.
12. 24159404. 2013. Suzuki. K. Reversed halo sign in tuberous sclerosis complex. Case Reports in Radiology. 2013. 1–4. Seyama. K. Hayashi. T. Yamashiro. Y. Shiraishi. A. Kuwatsuru. R. 10.1155/2013/428501. 3789275. free.
13. 11406664. 2001. Maruyama. H. Multifocal micronodular pneumocyte hyperplasia and lymphangioleiomyomatosis in tuberous sclerosis with a TSC2 gene. Modern Pathology. 14. 6. 609–14. Seyama. K. Sobajima. J. Kitamura. K. Sobajima. T. Fukuda. T. Hamada. K. Tsutsumi. M. Hino. O. Konishi. Y. 10.1038/modpathol.3880359. free.