Tubulolobular carcinoma of the breast

Definition

This is a rare subtype of breast carcinoma intermediate between ductal and lobular in differentiation. A criterion of 75% of the tumour showing a tubulolobular pattern has been set.

Histopathology

The tumour consists of small tubules and cell cords. Both components permeate in a targetoid pattern as for lobular carcinoma. A minor component (<25% of the tumour) may be pure tubular or pure lobular. Collision tumours are excluded. In most cases the cells are small with little cytoplasm and inconspicuous nucleoli. Some cases show apocrine metaplasia with eosinophilic cytoplasm, larger nuclei and more prominent nucleoli. An in situ component is common and may be lobular or mixed, less often pure ductal.

Immunohistochemistry

Tubulolobular carcinoma

Pure tubular carcinoma

Pure lobular carcinoma

tubular component

cell cords

E-cadherin

27/27

27/27

5/5

0/5

34bE12

25/27 (staining is cytoplasmic and often diffuse)

25/27 (staining is often paranuclear)

5/5

4/5

ER

17/17 (intense positivity)

PR

16/17 (intense positivity)

Her-2

0/10

Prognosis

The prognosis is probably better than for pure lobular but worse than for pure tubular carcinoma.

References

Wheeler, D. T., L. H. Tai, et al. (2004). "Tubulolobular carcinoma of the breast: an analysis of 27 cases of a tumor with a hybrid morphology and immunoprofile." Am J Surg Pathol 28(12): 1587-93.

This page last revised 5.1.2005.

	Tubulolobular carcinoma		Pure tubular carcinoma	Pure lobular carcinoma
	tubular component	cell cords	Pure tubular carcinoma	Pure lobular carcinoma
E-cadherin	27/27	27/27	5/5	0/5
34bE12	25/27 (staining is cytoplasmic and often diffuse)	25/27 (staining is often paranuclear)	5/5	4/5
ER	17/17 (intense positivity)
PR	16/17 (intense positivity)
Her-2	0/10