Penis & scrotum
Squamous cell carcinoma and variants
Basaloid carcinoma

Topic Completed: 1 April 2010

Minor changes: 13 February 2019

Copyright: 2002-2019,, Inc.

PubMed Search: Basaloid carcinoma penis

Alcides Chaux, M.D.
Antonio L. Cubilla, M.D.
Page views in 2019: 1,320
Page views in 2020 to date: 675
Cite this page: Chaux A, Cubilla AL. Basaloid carcinoma. website. Accessed July 10th, 2020.
Definition / general
  • Squamous cell carcinoma composed of uniform, small to intermediate cells in solid sheets or nests and often with central comedo-like necrosis
  • ICD-0: 8083 / 3
  • Glans is the preferred site but extension to coronal sulcus and inner foreskin is common
Diagrams / tables

Images hosted on other servers:

Yellow with focal necrosis

Clinical features
  • Aggressive, high grade and deeply invasive penile tumor
  • Inguinal nodal metastases in 50 - 100% (J Urol 2006;176:1431) and local recurrence in 36%
  • High mortality rate (21 - 67%)
Prognostic factors
  • Regional metastasis and mortality associated with tumor thickness > 10 mm and infiltration of corpus cavernosum (Am J Surg Pathol 1998;22:755)
Gross description
  • Flat, ulcerated, irregular mass with solid tan tissue replacing corpus spongiosum and invading tunica albuginea and corpus cavernosa
  • Mean tumor size of 3 - 4.5 cm
Gross images

Images hosted on other servers:

Yellow-white tumor

6 cm fibrous white soft tissue tumor

Microscopic (histologic) description
  • Closely attached nests of tumor cells, often with central comedo-like necrosis
  • Vertical growth pattern is typical
  • Composed of small to intermediate basophilic cells with scant cytoplasm, indistinctive cell borders and high mitotic / apoptotic rate
  • Occasionally peripheral palisading and focal central abrupt keratinization
  • May have peripheral clefts due to retraction artifact
  • Frequently associated with basaloid or warty penile intraepithelial neoplasia (Int J Surg Pathol 2004;12:351)
  • Prominent perineural and vascular invasion
Microscopic (histologic) images

AFIP images

Focal necrosis

Images hosted on other servers:

Closely packed nests

Starry sky appearance

Hyperchromatic nuclei

Fig 1C

Contributed by Alcides Chaux, M.D. and Antonio Cubilla, M.D.

Tumor nests

Pleomorphic cells

Basaloid differentiation

Differential diagnosis
  • Basal cell carcinoma: neoplastic cells have less atypia, tumor occurs usually in skin of shaft, nests have prominent peripheral palisading and characteristic myxoid stromal changes
  • Neuroendocrine carcinoma: similar morphology; immunohistochemistry for neuroendocrine differentiation may be useful
  • Poorly differentiated usual squamous cell carcinoma: more irregular nests, neoplastic cells with eosinophilic cytoplasm and distinct cellular boundaries, gradual (not abrupt) keratinization and clear tendency towards squamous differentiation
  • Urothelial carcinoma: more pleomorphism, features of urothelial differentiation usually evident in the invasive or in situ component, positive for uroplakin III and thrombomodulin
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