Penis & scrotum
Squamous cell carcinoma and variants
HPV associated squamous cell carcinoma
Basaloid carcinoma
Authors: Alcides Chaux, M.D., Antonio L. Cubilla, M.D.
Last author update: 1 April 2010
Last staff update: 28 October 2020
Copyright: 2002-2023, PathologyOutlines.com, Inc.
PubMed Search: Basaloid carcinoma penis
Table of Contents
Definition / general | Epidemiology | Sites | Etiology | Diagrams / tables | Clinical features | Prognostic factors | Treatment | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Differential diagnosisCite this page: Chaux A, Cubilla AL. Basaloid carcinoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/penscrotumbasaloid.html. 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
Epidemiology
- 4 - 10% of all penile carcinomas (Anal Quant Cytol Histol 2007;29:185)
- Median age 52 years (range 33 - 84 years)
Sites
- Glans is the preferred site but extension to coronal sulcus and inner foreskin is common
Etiology
- HPV detected in 71 - 81% of all cases (HPV 16 in 81% of all positive tumors, Am J Pathol 2001;159:1211)
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)
Treatment
- May require total penectomy, bilateral groin dissection and adjuvant chemotherapy from the onset (Am J Surg Pathol 2009;33:1299)
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
Positive stains
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
