# Lactating Adenoma in Pregnancy: Report of Three Cases

## TL;DR

This paper reports three cases of lactating adenoma in pregnant women, describing their clinical features and distinguishing them from other breast lesions.

## Contribution

The novelty lies in presenting three new clinical cases and emphasizing diagnostic criteria for lactating adenoma during pregnancy.

## Key findings

- Lactating adenoma presents as a circumscribed, painless, and mobile breast mass in the third trimester.
- Histological features include hyperplastic lobules with glandular formations and hobnailing phenomena.
- Immunohistochemical markers like cytokeratin 14 and p40 help distinguish lactating adenoma from other breast lesions.

## Abstract

Lactating adenoma is an infrequent benign stromal breast tumor mostly seen during pregnancy and lactation. This report seeks to enhance the literature by presenting three cases diagnosed with this condition, while also highlighting its histological subtypes, immunohistochemical characteristics, and differential diagnoses.

In all three patients, a circumscribed, painless, and mobile mass was found in the breast in the third trimester of pregnancy. Pathohistological examination revealed hyperplastic lobules with glandular formations in back-to-back arrangements showing more or less abundant hobnailing phenomena with intraluminal eosinophilic secretions and inconspicuous myoepithelial cell layer separated by fibrovascular stroma. The immune profile showed positive reaction for cytokeratin 14 and p40 markers, indicating the presence of myoepithelial cells and distinguishing these cases from other breast lesions.

Pathohistological and immunohistochemical analysis should be performed to differentiate these lesions from other benign lesions and malignant tumors.