Atypical adenomatous hyperplasia explained

Atypical adenomatous hyperplasia is a subtype of pneumocytic hyperplasia in the lung. It can be a precursor lesion of in situ adenocarcinoma of the lung (bronchioloalveolar carcinoma). In prostate tissue biopsy, it can be confused for adenocarcinoma of the prostate. The needle biopsy rate is less than 1%.

Pathology

Morphological differential diagnosis

• Multifocal micronodular pneumocyte hyperplasia (MMPH)^[1]
• in situ pulmonary adenocarcinoma (bronchioloalveolar carcinoma – BAC)

Variants

• multiple atypical adenomatous hyperplasia^[2]
• disseminated AAH^[3]

Histopathological images

See also

• EGFR
• KRAS

Notes and References

1. 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.
2. 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.
3. 19179908. 2009. Pastorino. U. Prolonged remission of disseminated atypical adenomatous hyperplasia under gefitinib. Journal of Thoracic Oncology. 4. 2. 266–7. Calabrò. E. Tamborini. E. Marchianò. A. Orsenigo. M. Fabbri. A. Sozzi. G. Novello. S. De Marinis. F. 10.1097/JTO.0b013e3181952930. 2318/84918. 35747902. free.