Penis & scrotum

Squamous cell carcinoma and variants

HPV independent squamous cell carcinoma

Carcinoma cuniculatum

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

Copyright: 2002-2023,, Inc.

PubMed Search: Carcinoma cuniculatum penis

Alcides Chaux, M.D.
Antonio L. Cubilla, M.D.
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Cite this page: Chaux A, Cubilla AL. Carcinoma cuniculatum. website. Accessed May 30th, 2023.
Definition / general
  • Rare, low grade variant of verruciform penile carcinoma with deeply penetrating and burrowing pattern of growth
  • More common in plantar surface of foot, first described in 1954 (Br J Surg 1954;42:245)
  • Cuniculatum: from "cuniculus," rabbit's burrow (hole)
  • Elderly men
  • Mean age 77 years (range 73 - 83 years)
  • Glans and coronal sulcus frequently involved
  • Multiple anatomical compartments usually affected
  • No evidence of HPV infection
Clinical features
  • Slow growing
  • Tumors may begin as small warts and slowly progress to larger tumors
  • No reported cases with regional nodal metastasis or cancer related death
Case reports
Gross description
  • Verruciform pattern of growth
  • Average size 6.3 cm (range 5 - 9 cm)
  • Tumor invade deep erectile tissues with a burrowing pattern of growth on cut section
  • Stroma tumor interface sharply delimited
  • Presence of cyst-like and sinus structures
  • Fistulae to preputial or shaft skin are common
Gross images

Images hosted on other servers:

Ulcerated verrucous carcinoma

Microscopic (histologic) description
  • Low grade keratinizing neoplastic nests resembling verrucous carcinoma
  • Hyperkeratosis, papillomatosis and marked acanthosis
  • Bulbous front of invasion
  • Cyst-like and sinus lumina filled with hyperkeratotic material
  • No / rare vascular and perineural invasion; no fibrovascular cores; no koilocytes
Microscopic (histologic) images

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

Cyst-like sinuses and tracts

squamous maturation
and extensive

Images hosted on other servers:


Verrucous carcinoma

Burrowing invasion of the dermis

Differential diagnosis
  • Mixed (hybrid) usual - verrucous carcinoma: verrucous carcinoma with foci of usual squamous cell carcinoma typically located at tumor front, absence of a burrowing pattern of growth
  • Verrucous carcinoma: similar in the exophytic component, usually limited to lamina propria or superficial corpus spongiosum and absence of a burrowing pattern of growth
  • Warty carcinoma: condylomatous papillae with prominent fibrovascular cores, conspicuous koilocytosis and jagged tumor front
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