33 Special Types of Invasive Breast Carcinoma: Diagnostic Criteria ...

Case 8
Case history: A 50 year old female with round firm beast mass.
Submitted diagnosis: Medullary Carcinoma (poorly differentiated invasive
breast carcinoma, overall mBR grade 3; nuclear grade 3, tubular grade 3,
mitotic grade 3).
MEDULLARY CARCINOMA
Background: Medullary carcinoma is defined in the WHO classification of breast
tumors (1) as a “well circumscribed carcinoma composed of poorly differentiated cells
with scant stroma, no glangular component and prominent lymphoid infiltration." The
diagnosis of “true” medullary carcinomas requires strict application of diagnostic
criteria; and, when done properly, some report that it constitutes ~5% of breast
carcinomas (2-5). Like others, I believe those tumors with atypical features are best
considered within the group of InvDC,NST (until additional studies indicate
otherwise)(6,7) or invasvie ductal carcinoma with medullary features (42).
Successful treatment by lumpectomy and primary radiotherapy has been reported (8),
and many (but not all) studies indicate an improved prognosis over InvDC,NST, when
compared stage for stage with InvDC,NST (2-4,9-12). For example, Moore and Foote
(9) reported that 11.5% of their patients with medullary carcinoma died of tumor
within five years, despite the fact that 42% of patients had axillary node metastases.
Richardson (4) reported that the 5-year disease-free survival of their 99 patients was
78%, with death due to disease in only 10%. There was 95% 20-year disease free
survival for stage I patients in this series and 61% for stage II patients (2). Patients
with medullary carcinoma tend to have a lower frequency of axillary node metastases
than patients with atypical medullary or InvDC,NST (3,11,10); and, when present,
nodal metastases are usually found in three or fewer nodes (3,10). Stage II medullary
carcinoma patients have a more favorable prognosis than comparable patients with
non-medullary carcinoma. But, patients with tumors larger than 3 cm or with four or
more positive nodes have high recurrence rates that are not appreciably different from
the recurrence rates of patients with infiltrating duct carcinoma.
Ellis et al. (13) and Periera et al. (14) do not report a significantly different survival
for all patients with medullary carcinoma, compared to patients with InvDC,NST (i.e.,
51% vs. 46%, respectively, at 10 years follow up). They emphasize that this holds
even when strict criteria are applied for the diagnosis. However, review of their data
show that the 10-year survival for mBR grade 3 InvDC,NST is 39%, whereas it is
51% for medullary carcinoma. All medullary carcinomas were mBR grade 3 in their
series. Possibly, this group will accept some improved survival for patients with
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