738 BRIT. J. SURG., 1973, Vol. 60, NO. 9, SEPTEMBER

INFARCTION OF FIBRO-ADENOMA OF THE BREAST BY JOSEPH NEWMAN AND LEONARD B. KAHN

DEPARTMENT OP PATHOLOGY, UNIVERSITY OF CAPE TOWN MEDICAL SCHOOL AND GROOTE SCHUUR HOSPITAL, CAPE TOWN, SOUTH AFRICA

SUMMARY

Infarction of benign lesions of the breast is very uncommon and may lead to difficulties in clinical and pathological diagnosis. Five instances of infarction occurring in a fibro-adenoma are described; in 2 of them thrombo-occlusive vascular changes were seen. The aetiology, pathogenesis, and helpful diagnostic features are discussed.

INFARCTION is a n infrequently reported complication of fibro-adenoma of the breast. In a review of the literature we have been able to find only I I such cases, of which 4 occurred during pregnancy and lactation

FIG. I.-Care 3. Cut surface of infarcted fibro-adenoma.

(Delarue and Redon, 1949; Wilkinson and Green, 1964; Pambakian and Tighe, 1971); i n none of these were vascular changes described. This article reports a further 5 cases and describes vascular lesions that were present in 2 of them; only I of the 5 cases was associated with pregnancy and lactation.

CASE REPORTS Case I.-A 25-year-old coloured female presented with

a tender lump in her breast which she had noticed 10 days prior to her admission in August, 1956. She was not pregnant and there were no other relevant clinical fea- tures. An excision biopsy was performed.

The specimen consisted of fibro-adipose tissue weighing 38 g. The cut surface revealed a 4 x 3-cm. well-encapsu- lated nodule with a variegated appearance. There were soft greyish-pink as well as firm white areas. Histologically, the lesion was well circumscribed and surrounded by compressed but otherwise normal breast tissue. It showed the features of a fibro-adenoma of predominantly intra- canalicular type. Except for a viable rim at the periphery, the tumour was necrotic but the original architectural pattern was still discernible. Within the necrotic tissue focal areas of interstitial haemorrhage were evident.

Several large vessels were seen at the periphery of the tumour and in the surrounding breast tissue, but they showed no evidence of either thrombo-occlusive or inflam- matory vascular disease. Within the necrotic areas many of the vessels were intensely congested. The features were those of a fibro-adenoma which had undergone recent infarction.

Case 2.-In August, 1960, a 40-year-old Caucasian female presented with a I-week history of a mobile lump in her right breast. An excision biopsy was performed.

The specimen consisted of breast tissue measuring 10 cm. in its greatest dimension. The cut surface showed two lobulated nodules. The larger nodule measured 6.5 cm., had a dark-red colour, and its appearance suggested a necrotic fibro-adenoma. The smaller nodule had the

FIG. 2.-Case 3. The architectural pattern of the fibro-adenoma is still obvious despite complete necrosis. H. and E. ( x 100.)

appearance of a typical fibro-adenoma. Histological examination confirmed the features of an intracanalicular fibro-adenoma. However, in the larger nodule there were extensive areas of necrosis with foci of interstitial haemor- rhage and congestion. Within these foci the original architecture of the fibro-adenoma was still preserved. At the periphery the tumour tissue was still viable and was infiltrated by acute and chronic inflammatory cells. Within a fibrous septum separating a lobule of viable from necrotic tissue there was a medium-sized vessel which was com- pletely occluded by thrombus. These features indicated a fibro-adenoma with large areas of recent infarction.

Case 3.-A 17-year-old coloured female presented in April, 1972, with a history of being aware of a lump in her right breast for 3 months. Before her admission she had developed a throbbing pain in the lump. There was no history of recent pregnancy or of trauma to the breast. On examination the lump was found to be mobile and non-tender; the axillary nodes were not palpable. The breast lump was excised.

The specimen consisted of a circumscribed tumour mass weighing 50 g. and measuring 4.5 x 4 x 3 cm. (Fig. I). It had a lobulated bulging cut surface with geo- graphically outlined haemorrhagic and tan-coloured areas. Microscopically, the lesion was a fibro-adenoma of mixed type. Except for a peripheral rim of viable tumour tissue,

NEWMAN AND KAHN: INFARCTION OF FIBRO-ADENOMA 739

most of the lesion was necrotic but with preservation of inflammatory cells as well as fibroblastic proliferation was the architectural pattern (Fig. 2). A mild lymphocytic present. There was no evidence of thrombo-occlusive or infiltrate was present at the margins of the infaraed areas. inflammatory vascular disease. The features were those A small artery was located adjacent to an infarcted area of a fibro-adenoma showing lactational change and and its lumen was occluded by recanalized thrombus extensive recent infarction.

FIG. 3.--Case 3. Viable fibro-adenoma is seen on the left and necrotic fibro-adenoma on the right. An artery showing occlusion of its lumen by recanalized thrombus is present in the fibrous septum (arrow). H. and E. ( x go.)

FIG. 4.--Case 3 . Detail of recanalized thrombus occluding a medium-sized artery in a fibrous septum. H. and E. ( x 150.)

FIG. S.--Case 4. Infarcted fibro-adenoma. Capsular surface on the right and cut surface on the left.

(Figs. 3, 4). The features were those of a fibro-adenoma with large areas of infarction.

Case 4.-In July, 1972, an IS-year-old coloured female presented with a 2-year history of a lump in her breast. She had first noticed the lump following trauma to her breast during a game of netball. The lump had slowly increased in size and was occasionally painful. Four months prior to her admission she had given birth and had breast-fed the baby from the opposite breast. The lump had not decreased in size during puerperium or lactation. On examination the presence of a mobile lump in the left upper outer quadrant was confirmed. The axillary nodes were not palpable. The lump was excised.

The specimen consisted of a well-circumscribed spherical mass measuring 6 cm. in diameter (Fig. 5). It had a bulging cut surface and a distinct tan colour. Most of the tumour mass appeared to be necrotic. Micro- scopically, the lesion was a fibro-adenoma in which the acinar epithelial cells showed lactational change. The circumscribed mass was surrounded by a compressed rim of breast tissue showing regressive postpartum change. Except for a rim of peripheral viable tumour tissue, most of the lesion was necrotic. In areas of necrosis there was a marked histiocytic infiltrate in response to liberated secretions (Fig. 6). At the junction between the viable and necrotic tissue an infiltrate of acute and chronic

FIG. 6.--Care 4. Histiocytic reaction in response to the libera- tion of secretions from the infarcted fibro-adenoma showing lactational change. H. and E. ( x 94.)

Case 5.-A 17-year-old coloured female presented with a mass in the right breast of I month's duration. Initially the lump was tender and the patient complained of a throbbing pain associated with it but these symptoms had subsided. She had been given antibiotics by her doctor who had diagnosed a breast abscess. There was no history of trauma. On examination a 5-cm. firm well- circumscribed mass was palpated and was thought to be a treated breast abscess or a fibro-adenoma; it was excised.

The specimen consisted of a well-encapsulated nodule 4.5 cm. in diameter with a necrotic-looking grey cut

740 BRIT. J. SURG., 1973, Vol. 60, NO. 9, SEPTEMBER

surface. Histologically, the peripheral rim of the lesion showed features of a pericanalicular fibro-adenoma while the bulk of the tumour was completely infarcted. No occluded feeding vessels were noted.

DISCUSSION Fibro-adenomas are common benign breast lesions

and in one large series (Wright and Symmers, 1966) they constituted 19 per cent of all benign breast lumps. There are very few reports of necrosis occurring in these lesions and several standard textbooks of pathology fail to mention this complica- tion (Wright and Symmers, 1966; Ackerman, 1968; Anderson, 1968; Evans, 1968; McDivitt, Stewart, and Berg, 1968). We have been able to find only a few references to infarction occurring in fibro- adenomas. Six such lesions occurring in non-pregnant women are recorded in the French literature by Delarue and Redon (1949). Wilkinson and Green (1964) have reported 2 instances of infarction in fibro-adenoma occurring during pregnancy and lactation, while Pambakian and Tighe (1971) recently reported I case of infarction of a fibro-adenoma unassociated with pregnancy and 2 cases occurring in association with pregnancy and lactation. We have been able to find 5 cases of infarction in a fibro- adenoma recorded in the surgical pathology files of the Groote Schuur Hospital from I950 to I972 but we have not systematically reviewed all the fibro- adenomas seen in this department. Two of these 5 cases were seen during the past 6 months; only I of the 5 was associated with pregnancy and lactation.

Other authors have been unable to demonstrate an anatomical cause for the infarction of fibro-adenomas and have postulated a relative vascular insufficiency secondary to an increased metabolic requirement such as occurs during pregnancy and lactation. Pambakian and Tighe (1971) were unable to account for the infarction of the fibro-adenoma that occurred in a postmenopausal patient. The infarcted fibro- adenoma in the present Case 4, who had recently been pregnant, displayed similar histological features to those described by Wilkinson and Green (1964), viz., a fibro-adenoma with lactational changes and infarc- tion without obvious anatomical cause. Two of the present lesions resembled one of the cases described by Pambakian and Tighe (1971) in that the infarction occurred in the absence of pregnancy and without demonstrable vascular lesions to account for the infarction. However, in the two other lesions we were able to demonstrate thrombo-occlusive vascular changes in the feeding vessels. As far as we are aware this is the first documentation of such changes in this condition. These vessels subtended the areas of infarction and were situated in fibrous septa separating areas of infarcted from viable tumour. The areas of infarction seemed disproportionately large, consider- ing the size of the vessel involved. Although it is possible that these thrombosed vessels may have been the primary cause of the infarction, the possibility of secondary thrombosis following the infarction cannot be entirely excluded. I t is interesting to speculate on the possible role of mechanical factors, as

fibro-adenomas are usually very mobile in the breast and could theoretically undergo torsion with compro- mise of their blood-supply. If this were an important aetiological factor it is surprising that infarction is not a more frequent complication in fibro-adenomas. The theory of relative vascular insufficiency occurring during phases of increased metabolic activity and nutritional requirement may explain the necrosis described in fibro-adenomas in pregnancy (Wilkinson and Green, 1964; Pambakian and Tighe, 1971). This same mechanism has been postulated to be the cause of necrosis that occurs in lactational adenomas (Hasson and Pope, 1961). However, it is difficult to understand why infarction of fibro-adenomas during pregnancy and lactation is so infrequently recorded.

I t is of paramount importance for the pathologist to recognize infarction in a fibro-adenoma and not to mistake it for necrotic breast carcinoma. Delarue and Redon (1949) described these tumours as having clinically simulated carcinoma, viz., hardness, fixation, and enlarged axillary nodes. The clinical diagnosis of carcinoma was made with such confidence that 4 of their 6 patients underwent mastectomy without the benefit of prior excision biopsy and frozen-section examination. In none of our patients was the diag- nosis of carcinoma considered. However, the surgical pathologist always regards necrosis in tumours with suspicion so that examination of necrotic areas in a fibro-adenoma may give rise to diagnostic difficulties, especially on frozen-section examination. The necrotic ductular and glandular outlines may bear a superficial resemblance to adenocarcinoma, while the collection of foamy histiocytes lying loosely within the necrotic tumour tissue spaces, as seen in our Case 4, may simulate a mucoid carcjnoma. However, the macroscopical features as well as the architectural pattern, even in the necrotic areas, are quite obviously those of necrosis in a fibro-adenoma. Sections taken from the periphery usually reveal viable fibro-adenomatous tissue so that confusion between carcinoma and necrosis in a fibro-adenoma should not occasion diagnostic difficulty, even on frozen-section examination.

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