Impalpable breast lesions diagnosed by mammography: incidence of histologically confirmed malignancy.
OBJECTIVE
To evaluate the suitability of currently applied mammographic criteria for the early diagnosis of subclinical tumours by comparing radiological findings with the final histological diagnosis.


METHODS
Open study.


METHODS
District hospital, Denmark.


METHODS
151 Women who underwent needle biopsy of 161 occult breast lesions that had been diagnosed by mammography during the period 1986-90.


METHODS
Definitive operation if frozen section at the time of needle biopsy indicated malignancy. Radiographic examination of the specimen ensured that the abnormal area had been excised.


METHODS
Correlation of mammographic and histological findings.


RESULTS
Eight foci showed carcinoma in situ and 33 invasive carcinoma; 10 of the 33 had lymph node metastases. Foci with mammographic masses had a significantly higher risk of malignancy than those without (25/70, 37%, compared with 8/91, 17%, p = 0.005). Spiculated foci with clustered calcifications had the highest risk of malignancy (6/11, 54%). 16/87 foci in women less than 50 years old contained malignant disease compared with 25/74 in women aged 50 or more (p = 0.04). A fifth of the frozen sections contributed nothing to the diagnosis. The incidence of malignant disease in impalpable lesions of a quarter is similar to the reported incidence in palpable mammary tumours, but metastases at the time of diagnosis are appreciably less common (30% compared with 50%).


CONCLUSIONS
The currently applied mammographic criteria are particularly helpful to patients under the age of 50.
Department of Surgery, KAS Glostrup, Copenhagen, Denmark.
L P
LP
Rothman
T B
TB
Harvald
H
H
Overgaard
D000328:Adult; D000368:Aged; D001707:Biopsy, Needle; D001940:Breast / Q000473:pathology*; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D016504:Breast Self-Examination; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis; D008327:Mammography; D008875:Middle Aged; D010173:Palpation