Case report: Papillary squamous cell carcinoma of the penis

<p><strong>Case history</strong></p> <p>62-year-old male with a verruciform tumor located in distal penis and involving glans.</p> <p>&nbsp;</p> <p><strong>Histologic findings</strong></p> <p>The microphotographs show an exophytic verruciform tumor mass characterized by papillomatosis, slight to moderate acanthosis, and hyperkeratosis. Papillae are complex, some with blunt and others with spiky tips. Fibrovascular are present in most but not all papillae and are irregularly shaped. Tumor base is jagged and there is a prominent stromal reaction. Neoplastic cells in papillae and infiltrative tumor nests are well to moderately differentiated (grades 1-2) and no koilocytic atypia is observed.</p> <p>&nbsp;</p> <p><strong>Discussion</strong></p> <p>Verruciform penile tumors comprise about one-quarter of all penile squamous cell carcinomas (SCC) and include papillary, verrucous, and warty carcinomas, as well as giant condylomas and carcinoma cuniculatum. As a group, verruciform carcinomas are characterized by the presence of papillomatosis, acanthosis, and hyperkeratosis. However, there are distinctive morphological features for each one of these tumors.&nbsp;For papillary SCC, the most distinguishing feature is the presence of complex papillae with irregularly shaped fibrovascular cores. Papillary carcinomas tend to be polymorphic with some areas exhibiting condylomatous papillae and others with a more verrucous-like aspect. Fibrovascular cores are readily found in the former and are scant or even absent in the latter.</p> <p>Another important clue in the differential diagnosis with other verruciform tumors is the presence of a jagged tumor-stroma interface. In verrucous and cuniculatum&nbsp;carcinomas the tumor front is broad-based. The absence of koilocytosis allows the distinction from warty carcinomas and giant condylomas, tumors in which koilocytes are conspicuous. HPV status may be helpful in problematic cases, since in papillary carcinomas the HPV detection rate is very low or even null. Immunohistochemistry for p16^INK4a is also useful since the vast majority of papillary carcinomas do not overexpress this protein.&nbsp;In order for a penile tumor to be considered as p16^INK4a positive&nbsp;all neoplastic cells should be stained. Cases like this one in which some cells stain and others do not should be regarded as negative for p16^INK4a overexpression.</p> <p>The inguinal metastatic rate of penile papillary carcinomas is very low and the prognosis is good. Less than one-fifth of all patients present inguinal involvement and even in these cases the mortality rate is low. Even when tumors invade penile erectile tissues prognosis is good as long as no high-grade areas (observed in a minority of the patients) are identified.</p> <p>Clinically patients should be managed using risk-group stratification systems and taking into account histological grade, anatomical level of maximum tumor infiltration, and the presence of vascular and perineural invasion.&nbsp;</p> <p>&nbsp;</p> <p><strong>References</strong></p> <p><a href="https://www.ncbi.nlm.nih.gov/pubmed/20061934">Chaux et al. Am J Surg Pathol. 2010 34(2): 223-30</a></p> <p><a href="https://www.ncbi.nlm.nih.gov/pubmed/22641955">Chaux &amp; Cubilla. Semin Diagn Pathol. 2012 29(2): 72-82</a></p> <p><a href="https://www.ncbi.nlm.nih.gov/pubmed/22641955">Chaux &amp; Cubilla. Semin Diagn Pathol. 2012 29(2): 67-71</a></p>