Breast nonmalignant
Benign tumors
Clear cell "sugar" tumor

Topic Completed: 1 January 2017

Minor changes: 5 September 2019

Copyright: 2002-2019,, Inc.

PubMed Search: Clear cell sugar tumor breast

Monika Roychowdhury, M.D.
Page views in 2019: 1,092
Page views in 2020 to date: 711
Cite this page: Roychowdhury M. Clear cell "sugar" tumor . website. Accessed May 27th, 2020.
Definition / general
  • Very rare tumor in breast of epithelioid to spindle cells with clear to eosinophilic granular cytoplasm and distinct cell borders, positive for melanocytic markers
Essential features
  • Rare tumor differentiating towards Perivascular Epithelioid Cells
  • Belongs to PEComa family of tumors, extremely rare in breast
  • Microscopy shows spindle to epithelioid cells with clear or eosinophilic cytoplasm and distinct cell borders
  • Stains positive for melanocytic markers
  • Treatment by excision; new drug rapamycin under investigation
Clinical features
  • Benign behavior
Case reports
  • Excision
  • Trial with rapamycin in progress; may become useful for malignant cases
Microscopic (histologic) description
  • Epithelioid to spindle cells with clear cytoplasm and distinct cell borders
Microscopic (histologic) images

Images hosted on other servers:

Lung tumor is HMB45+

Positive stains
Negative stains
Molecular / cytogenetics description
  • Related to the genetic alterations of tuberous sclerosis complex, an autosomal dominant disease due to loss of TSC1 (9q34) or TSC2 (16p13.3) genes which seem to have a role in regulation of the Rheb / Mtor / p70S6K pathway
Differential diagnosis
  • Glycogen rich (clear cell) carcinoma: large nests of clear cells with hyperchromatic nuclei, mild / moderate atypia and pleomorphism; invasive; keratin+, PAS+ diastase sensitive; negative for HMB45 and MelanA
Additional references
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