Invasive lobular carcinoma: correlations between morphological features, vimentin expression, oestrogen receptor status and prognosis

Thirteen morphological features were assessed by semiquantitive methods in 107 cases of invasive lobular carcinoma of the breast (ILC). Only two features were found to be statistically significant with respect to survival: abundance of cytoplasm and alveolar formation. The patients with tumours characterized by scanty cytoplasm and absence of alveolar structures had poorer prognosis. Moreover, in 57 cases oestrogen receptor (ER) status and vimentin expression were assessed. Eighty one per cent of cases were ER positive with values higher than that reported in infiltrating (ductal) carcinomas of no special type. The alveolar variant of ILC were most commonly ER positive (94%). Vimentin expression was found in five cases (9%), but strong reaction (more than 10% positive cells) was seen in three tumours. Neither ER status nor vimentin expression showed significant correlation with survival in a Cox model. The influence of tumour size, subtype of carcinoma and axillary lymph node status on survival was analysed. The solid type of the ILC and the number of involved lymph nodes had a statistically significant correlation with poorer prognosis.