BREAST CYTOPATHOLOGY

Glycogen-Rich, Clear Cell Carcinoma
Clinical Features
• Glycogen-rich, clear cell carcinoma is a rare variant of
invasive breast carcinomas, comprising 1%–3% of all breast
carcinomas.
• The reported age ranges from 41 to 78 years, with a median
age of 57 years.
• The clinical presentation is similar to ductal carcinomas
NOS.
• This variant is considered to be more aggressive than the
usual ductal carcinoma NOS, with an overall higher incidence
of lymph node metastasis.
Cytomorphologic Characteristics
• The key histologic feature is the presence of neoplastic
cells the majority of which have abundant clear cytoplasm
containing glycogen.
• The neoplastic cells have sharp borders with clear or finely
granular cytoplasm, which is periodic acid-Schiff positive
and diastase labile.
• The nuclei are hyperchromatic, with prominent nucleoli.
• The hormone receptor status is similar to ductal carcinomas
NOS.
Pitfalls and Differential Diagnosis
• Differential diagnosis of glycogen-rich, clear cell carcinomas
includes other “clear cell tumors” such as lipid-rich
carcinoma, clear cell hidradenoma, adenomyoepithelioma,
and metastatic renal cell carcinomas.
• Ancillary studies including the use of immunohistochemistry
are of immense value in avoiding diagnostic pitfalls.
Apocrine Carcinoma
Special Types of Breast Carcinomas 121
Clinical Features
• Pure apocrine carcinoma of the breast is rare, accounting
for 0.3%–4% of all breast carcinomas.