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

eported 4- to 5-fold increased risk for the subsequent development of invasive breast
carcinoma with a 10% absolute risk in 10 years (48, 50). ALH with duct involvement
has a 7-fold increased risk, and ALH and a positive family history of breast carcinoma
in a first degree relative increase the risk to 8- to 11-fold (44-46, 50).
Clinicopathologic features: LCIS has no distinctive gross appearance nor does it have
a specific microcalcification pattern. Indeed, when calcospherites are present they are
usually in adjacent benign structures or are apparently "overrun" by an ingrowth of
LCIS cells (47). Classical LCIS is characterized by a group of acini and/or ductules
filled by a monotonous (often noncohesive) population of small cells with regular
nuclei, evenly dispersed chromatin, and inconspicuous nucleoli. The cytoplasm is
scant and finely granular to clear; mitotic figures are rare.
As Page and Anderson state, "consistency in diagnosis of LCIS is fostered by
requiring that each of the following criteria be fulfilled: 1. the characteristic and
uniform cells must comprise the entire population of cells in a lobular unit, 2. there
must be filling of all the acini (no interspersed, intercellular lumens), and 3. There
must be expansion and/or distortion of at least one-half the acini in the lobular
unit...Lesser degrees of involvement are diagnosed as ALH, a diagnosis carrying a
lesser risk of subsequent carcinoma" (48). Extension of the cells characteristic of
ALH/LCIS (lobular neoplasia) into segmental ducts does not allow the diagnosis of
LCIS, unless the above stated criteria
are met in at least one lobular unit (48). Yet, ALH with duct involvement should lead
to the initiation of a careful search for LCIS by ordering level sections, submitting
additional tissue, and/or slide reexamination.
Differential diagnosis: Variant patterns of LCIS that can be mistaken for ductal
carcinoma in situ (DCIS) occur. In the most common variant pattern, the entire
population of LCIS cells are not small and uniform (type A cells), but rather, are an
admixture of tumor cells with more abundant cytoplasm and larger, more pleomorphic
nuclei sometimes containing nucleoli (type B cells)(17). The large-cell variant can
develop apocrine differentiation (11) or form signet-ring cells of varying sizes (15,16).
In these instances DCIS enters into the differential diagnosis. The diagnostic problem
is further complicated by well-documented examples of DCIS plus LCIS occurring
within the same biopsy and even the same duct (49). Moreover, occasional microacini
may form in ducts involved by cells with all the cytologic features of classical LCIS.
Indeed, Page et al. (50) presented a photograph they designated as depicting the "gold
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