Penis & scrotum

Squamous cell carcinoma and variants

HPV associated squamous cell carcinoma

Basaloid carcinoma

Last author update: 1 April 2010
Last staff update: 28 October 2020

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PubMed Search: Basaloid carcinoma penis

Alcides Chaux, M.D.
Antonio L. Cubilla, M.D.
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Cite this page: Chaux A, Cubilla AL. Basaloid carcinoma. website. Accessed June 9th, 2023.
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 PathOut server:

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 PathOut server:

Yellow-white tumor

Images hosted on other servers:

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

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

Tumor nests

Pleomorphic cells

Basaloid differentiation

AFIP images

Closely packed nests

Starry sky appearance

Hyperchromatic nuclei

Focal necrosis

Images hosted on other servers:

Fig 1C: basaloid carcinoma

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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