A comparative study of pure tubular and tubulolobular carcinoma of the breast.

Tubular carcinoma is a distinctive subtype of invasive, well-differentiated mammary ductal carcinoma that has a good prognosis when treated by modified radical mastectomy. Little is known about tubulolobular carcinoma. The purpose of this study was to compare the frequency of prognostic factors in pure tubular carcinoma (PTC) and tubulolobular carcinoma (TLC). We studied 90 cases of pure PTC and 17 cases of TLC. The following results were found for PTC: size 0.5 to 1.8 cm (mean, 1.2 cm); multifocality in 18 of 90 cases (20%); axillary lymph-node dissection performed in 51 patients; positive axillary lymph nodes in six of 51 cases (12%); recurrences in one of 90 cases (1%), local. The following results were found for TLC: size 0.6 to 2 cm (mean, 1.3 cm); multifocality in five of 17 cases (29%); axillary lymph-node dissection performed in 14 patients; positive axillary lymph nodes in six of 14 cases (43%); recurrences in two of 17 cases (12%); one local and one systemic, each after mastectomy. The relationship between multifocality and positive axillary lymph nodes was as follows: In PTC, the percentage of positive axillary lymph nodes in multifocal cases was 33%, and in nonmultifocal cases, 7%; in TLC, the percentage of positive axillary lymph nodes in multifocal cases was 60% and in nonmultifocal cases, 33%. In conclusion, multifocality and positive axillary lymph nodes were more frequent in TLC than in PTC. Multifocality appeared to predispose to positive lymph nodes in both PTC and TLC. The distribution of prognostic factors suggest that TLC is a higher-grade lesion than PTC. Long-term follow-up is needed to correlate multifocality with recurrence after breast conserving therapy.