a twenty one year old primi gravida at six months gestation presented with a history of rapidly enlarging lump in the left breast associated with pain . on examination ,
a mass approximately measuring 20 x 14 cm was present in the upper and lower quadrants of the left breast .
the specimen received by the pathology laboratory measured 16 x 10 x 5cms and weighed 750 gm ( fig.1 ) . the enucleated specimen :
the external surface was lobulated and the cut surface was nodular with focal white areas .
haematoxylin and eosin stained four - micron sections showed a well circumscribed tumor composed of hyperplastic acini retaining the configuration of normal breast lobules ( fig.2 ) .
lactating adenomas present as small , well circumscribed , freely mobile masses during pregnancy or lactation .
benign breast tumors associated with pregnancy can be of different types . in a study of 37 cases of benign breast tumors associated with pregnancy by o hara et al ,
only eight cases were lactating adenomas.(1 ) the others were fibroadenomas with lactational changes and tubular adenomas . lactating adenoma is a rare tumor and there are differing views on its histogenesis .
james et al considered lacating adenoma to be a pure and readily recognisable morphological form clearly distinguishable from tubular adenoma and fibroadenoma that is always related to current or recent pregnancy.(2 ) according to them , most tumors diagnosed as lactating adenomas are diagnosed during pregnancy and do not have lactational secretion .
the secretory changes seen are similar to the physiological changes of pregnancy in the adjacent breast tissue .
this is also supported by slavin et al , who in a study of 30 cases of nodular breast lesions of pregnancy , described 12 lesions that fitted with the description of lactating adenoma . according to slavin et al , lactating adenomas are nodules of physiologic lobular proliferation which become more prominent than the adjacent breast tissue and appear clinically to be a distinct mass and histologically resemble focal exaggerated physiological hyperplasia.(3 ) hertel et al however proposed that lactating adenomas arise in preexisting adenomas.(4 ) in a study by hertel et al , five of the seven postpartum patients with tubular adenomas , first observed the lump during pregnancy , leading to the authors conclusion that tubular adenomas and lactating adenomas are two ends of a spectrum , the latter with secretory changes associated with physiological states of pregnancy . both the views are given in the latest who fascicle on breast tumors , that is to say that a lacating adenoma is considered as a tubular type adenoma that may show extensive secretory changes in the epithelial cells during pregnancy and lactation.(5 ) it has also been suggested that such lesions represent focal accumulation of hyperplastic lobules .
usually , lactating adenomas are slow growing tumors which are smaller than 5 cm in size and are well demarcated from the surrounding breast tissue.(6 ) in a series of 14 lactating adenomas by james et al , most of the tumors were 2.5  3.5 cm in size .
they reported a giant breast mass which grew to a maximum size of 25 x 18cms.(7 ) the present case measured 16cms in diameter and qualifies for the second largest reported case of lactating adenoma .
sonologically , lactating adenomas are oval , sharply circumscribed , solid hypoechoic mass which can have a prominent central tubular structure presumed to be a dilated duct.(8 ) lactating adenomas are characterised by glands with a tubuloalveolar architecture and florid secretory features .
the histologic changes relate to the stage of pregnancy and approximate the changes in the adjacent breast .
if removed during pregnancy , the secretory changes are much less pronounced than in the tumor removed postpartum ( 6 ) as was observed in the present case .
the characteristic microscopic features of the tumors that come in the differential diagnosis is discussed by ohara , james and slavin.(1,2,3 ) tubular adenomas are characterised by uniform closely approximated tubular structures lined by epithelial and myoepithelial cells with little or no cytoplasmic vacuolisation .
fibroadenoma with secretory hyperplasia should be distinguished from lactating adenoma ; the latter lacks the characteristic stroma in a fibroadenoma .
rapid increase in size in a lactating adenoma can be due to infarction.(9 ) reeves et al have also described rapid increase in size in their report of giant lactating adenoma .
( 7 ) even though there was a history of pain and rapid growth , there was no evidence of infarction in the present case .
huge size and rapid increase in size can lead to a mistaken clinical diagnosis of malignancy .
enucleation is the recommended treatment for lactating adenomas as there is a low risk of recurrence .
( 7 ) bromocriptine can suppress lactation , the benefits of tumor shrinkage must be weighed against the cessation of lactation in a mother who is breast feeding . in summary
we report a case of a lactating adenoma presenting as a giant breast mass . in a case of rapidly enlarging breast mass in a pregnant lady
 lactating adenoma is one of the breast tumours associated with pregnancy . 
 a case of lactating adenoma , unusual on account of its huge size , is presented . 
 large size and history of rapid growth can lead to a mistaken diagnosis of malignancy . 
 a review of the literature of this particular tumour with the different views on its histogenesis and the differential diagnoses are also discussed . 
INTRODUCTION
CASE REPORT
DISCUSSION