Carcinoma in a fibroadenoma.

AI Sarela, AA Madvanur, ZF Soonawala, HK Shah, AA Pandit, AB Samsi 
 Department of General Surgery and Pathology, Seth GS Medical College, Parel, Mumbai.

Correspondence Address:
A I Sarela
Department of General Surgery and Pathology, Seth GS Medical College, Parel, Mumbai.

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::   Introduction

A fibroadenoma is a benign Tumour which is commonly found in the breasts of young women. A malignant change rarely occurs within a fibroadenoma and usually takes the form of a sarcoma[1]. The occurrence of a carcinoma within a fibroadenoma is uncommon with only a little over 100 cases being reported in literature[2]. There are only two documented cases of a carcinoma arising in a fibroadenoma in association with another distinct primary tumour in the same breast[3],[4]. We are reporting the third such case.

::   Case report

KKD, a 56-year-old post menopausal woman, noticed a painless hard lump in her right breast about two months prior to reporting to us. She had borne two children but had breast-fed neither. She had no family history of breast cancer and had received no hormonal therapy.

Clinical examination revealed a 2 cm x 3 cm hard, irregular lump with restricted mobility and puckering of the overlying skin in the upper outer quadrant (UOQ) of the right breast. There was another 2 cm x 2 cm firm, freely mobile subareolar lump in the same breast. A single firm lymph node was palpable in the right axilla.

FNAC of the UOQ lump was suggestive of infiltrating duct carcinoma while that of the subareolar lump was reported as benign. No distant metastases were discovered on investigation.

A right modified radical mastectomy was performed. Histopathological examination showed the subareolar lump to be a fibroadenoma of the intracanalicular variety with a focus of in situ lobular carcinoma, limited to the fibroadenoma [Figure:1] & [Figure:2]. The UOQ lump was an infiltrating duct carcinoma. The intervening parenchyma between the two lumps was normal. There were metastatic deposits in three axillary lymph nodes.

::   Discussion

A carcinoma arising in a fibroadenoma is quite an uncommon occurrence. The mean age of occurrence is 42.4 year[5]. This corresponds to the peak age of lobular in situ breast carcinoma, but is about 20 years later than the peak age of occurrence of fibroadenomas.

Fibroadenomas are not usually considered to be a risk factor for carcinoma, but dissenting views do exist[6]. Mostwitz has reported that the risk for developing a carcinoma is three times higher in those with a fibroadenoma[7]. A carcinoma arising in a fibroadenoma may be considered as chance occurrence of location. as the epithelial component of a fibroadenoma is subject to the same stimuli as the rest of the breast parenchyma[8]. Azzopardil states that carcinoma involving a fibroadenoma may be:

1. Carcinoma arising in the adjacent breast tissue engulfing and infiltrating a fibroadenoma.

2. Carcinoma in the crevices of a fibroadenoma as well as in the adjacent breast tissue.

3. Carcinoma restricted entirely, or at least dominantly, to a fibroadenoma.

One must exclude invasion of a fibroadenoma by carcinoma arising in the surrounding tissue to avoid false reports of carcinoma arising within a fibroadenoma.

McDivitt and Farrow[9], have published the first comprehensive review of this problem. Out of 26 cases. 50% were in situ lobular carcinoma and 11 % were infiltrating lobular carcinoma. In situ ductal carcinoma was reported in 22% of their cases, while the remaining were infiltrating ductal carcinoma. The surrounding breast parenchyma was involved in 33% of the cases. Pick and lossifides[5] reviewed 62 cases of carcinoma is situ. In 42% of the cases, the surrounding breast parenchyma was involved as well. Carcinoma develops in the contralateral breast of 20% of the patients presenting with carcinoma in a fibroadenoma[9].

There are no definite clinical criteria to suggest that malignant change has occurred in a fibroadenoma. The diagnosis is invariably reached on histopathological examination of the Tumour. A diagnosis of infiltrating lobular carcinoma or ductal adenocarcinoma within a fibroadenoma warrants that the patient should be offered an ipsilateral simple mastectomy. An axillary clearance may be added to the mastectomy (Auchincloss procedure). Excision only, with followup by mammographic monitoring of the breast, having a 1015% risk of developing invasive carcinoma in a fibroadenoma, remains controversial. The choice lies between follow up only, after an adequate excision, and immediate simple mastectomy. Goldman[10] advocates a random biopsy of the contralateral breast in addition to an ipsilateral simple mastectomy.

The prognosis is good, mainly because the fibroadenoma leads to an early diagnosis.

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