Invasive breast carcinoma - IARC

A
B
Fig. 1.137 A Lipoma. Intraparenchymal well circumscribed mature fat tissue. B Angiolipoma. Well circumscribed mature fat tissue separated by a network of small
vessels. C Cellular angiolipoma. Patches of solid, spindle cell proliferation are typically present.
C
Inflammatory
myofibroblastic tumour
Definition
A tumour composed of diff e re n t i a t e d
myofibroblastic spindle cells accompanied
by numerous inflammatory cells.
ICD-O code 8825/1
Synonyms
Inflammatory pseudotumour, plasma cell
granuloma.
Epidemiology
I n f l a m m a t o ry myofibroblastic tumour
(IMT) is a heterogeneous clinicopathological
entity {1845} that may occur at any
anatomical location. There is uncert a i n t y
as to whether IMT is reactive or neoplastic
in nature. Some authors re g a rd IMT as
a low grade sarcoma {1845}. Only rare
cases of IMT have been re p o rted in the
b reast {276,467,2235,3183}.
Clinical features
IMT usually presents as a palpable circumscribed
firm mass.
Macroscopy
Gross examination usually shows a well
circumscribed firm white to grey mass.
Fig. 1.138 Lipoma. Well circumscribed, lobulated
mass of 11 cm.
Histopathology
The lesion consists of a proliferation of
spindle cells with the morphological and
immunohistochemical features of myofibroblasts,
arranged in interlacing fascicles
or in a haphazard fashion, and variably
admixed with an inflammatory component
of lymphocytes, plasma cells and
histiocytes.
IMT should be distinguished from other
benign and malignant spindle cell
lesions occurring in the breast. The hallmark
of IMT is the significant inflammatory
cell component.
Prognosis and predictive factors
Although the clinical behaviour of IMT
cannot be predicted on the basis of histological
features, in the breast most
reported cases have followed a benign
clinical course after complete surgical
excision {276,467,2235}, with the exception
of a bilateral case with local recurrence
in both breasts after 5 months
{3183}. Additional cases with longer follow-up
are needed to define the exact
clinical behaviour.
Lipoma
Definition
A tumour composed of mature fat cells
without atypia.
ICD-O code 8850/0
Epidemiology
Although adipose tissue is quantitatively
an important component of the normal
breast tissue, pathologists rarely encounter
intramammary lipomas. Subcutaneous
lipomas are more often
resected. Most common lipomas become
apparent in patients 40-60 years
of age.
Clinical features
Lipomas usually present as a slow gro w-
ing solitary mass with a soft doughy cons
i s t e n c y.
Macroscopy
Lipomas are well circumscribed, thinly
encapsulated round or discoid masses;
usually less than 5 cm in diameter.
Histopathology
Lipomas differ little from the surro u n d i n g
fat. They may be altered by fibrous tissue,
often hyalinized or show myxoid changes.
S e c o n d a ry alterations like lipogranulomas,
lipid cysts, calcifications, may occur as a
result of impaired blood supply or trauma.
Variants of lipoma
These include angiolipoma {1268,2876,
3232} which, unlike angiolipomas at
other sites, in the breast are notoriously
painless. Microscopy reveals mature fat
cells separated by a branching network
of small vessels that is more pronounced
in the sub capsular areas.
C h a r a c t e r i s t i c a l l y, thrombi are found in
some vascular channels. Some lesions
rich in vessels are called cellular angiolipomas.
Other variants which have been described
in the breast include spindle cell
Fig. 1.139 Adenolipoma. Well circumscribed
mature fat containing organoid glandular tissue.
Mesenchymal tumours
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