Carcinoma cuniculatum capitis. A variant of squamous cell carcinoma of the skin

Cutaneous Squamous Cell Carcinoma: Review of the Eighth Edition of the American Joint Committee on Cancer Staging Guidelines, Prognostic Factors, and Histopathologic Variants

Cutaneous squamous cell carcinoma is the second most common form of nonmelanoma skin cancer after basal cell carcinoma and accounts for the majority of nonmelanoma skin cancer-related deaths. In 2017, the American Joint Committee on Cancer revised the staging guidelines of cutaneous squamous cell carcinoma to reflect recent evidence concerning high-risk clinicopathologic features. This update reviews the literature on prognostic features and staging, including the eighth edition of the American Joint Committee on Cancer Staging Manual. A wide range of histopathologic variants of cutaneous squamous cell carcinoma exists, several of which are associated with aggressive behavior. A review of cutaneous squamous cell carcinoma variants, emphasizing diagnostic pitfalls, immuhistochemical findings and prognostic significance, is included. Of note, the eighth edition of the American Joint Committee on Cancer Staging Manual refers to squamous cell carcinoma of the head and neck only.

Verrucous carcinoma of the axilla: case report and review

BACKGROUND

Verrucous carcinoma, a variant of squamous cell carcinoma, is distinct from squamous cell carcinoma in morphology and behavior. It preferentially occurs on the oropharyngeal mucosa, the urogenital mucosa, and the soles. In contrast to its malignant clinical picture, the tumor grows locally invasive but is histologically benign and metastasizes rarely.

METHODS

We report the uncommon occurrence of a large verrucous carcinoma on apparently uninvolved skin in the right axilla in a 47-year-old male.

RESULTS

Histologic examination reveals a cauliflower-like tumor consisting of deep invaginated epidermal proliferation with rabbit burrow-like, keratin-filled sinus formations; the basement membrane, however, remains intact. Immunohistology showed positivity for pancytokeratin (KL-1) and cytokeratin (CK) 18 and negativity for CK7, and assessment of the proliferative activity of the tumor cells revealed low percentage of Ki-67 expression. Furthermore, there were only scattered cells expressing p53 or bcl-2. Polymerase chain reaction excluded the presence of human papillomavirus. After complete excision, no signs of recurrence occurred over a follow-up period of three years.

CONCLUSION

Verrucous carcinoma should be distinguished from typical squamous cell carcinoma. The clinicopathological features, differential diagnosis, and therapy are discussed here together with the molecular biologic aspects of the tumor.

Carcinoma cuniculatum of the jaw: a rare variant of oral carcinoma

Carcinoma cuniculatum is a rare variant of carcinoma usually involving the foot. Only 13 cases have been described in the oral cavity, none of which was in the English-language literature. We describe a 56-year-old man who presented with a soft exophytic mass in the maxillary gingiva, alveolar bone destruction, and loosening of the teeth. Histopathologic study revealed thin papillary projections covered by a thick keratin layer in the superficial areas and multiple, branching keratin-filled crypts surrounded by well-differentiated squamous epithelium with only mild cytologic atypia but frequent mitosis. Immunohistochemistry results of p53 and polymerase chain reaction analyses for human papillomavirus 6, 11, 16, and 18 DNA were negative. The diagnosis was carcinoma cuniculatum of the jaw. The literature on this unusual oral pathosis is reviewed and the diagnostic challenge described. We suggest that carcinoma cuniculatum may sometimes be misdiagnosed as squamous cell carcinoma or verrucous carcinoma and, therefore, might be more prevalent than the small number of published cases implies.

Cutaneous verrucous carcinoma

Verrucous carcinoma is a rare, low-grade, well-differentiated squamous cell carcinoma most commonly seen on mucosa. It has been infrequently reported to occur on the skin, where it is a slow-growing and locally aggressive tumour. It is not uncommon for cutaneous verrucous carcinomas to be mistaken for the more frequent verruca vulgaris and treated accordingly. Three cases of cutaneous verrucous carcinoma are presented with the medical history and follow-up data. Surgery is the treatment of choice; these lesions may sustain a potentially anaplastic transformation after radiation therapy.

Verrucous carcinoma of the skin and mucosa

The concept of verrucous carcinoma as a clinicopathologic variant of squamous cell carcinoma is worthy of recognition. It is known by a confusing array of names, such as Ackerman's tumor, Buschke-Loewenstein tumor, florid oral papillomatosis, epithelioma cuniculatum, carcinoma cuniculatum, and cutis papillomatosis carcinoides of Gottron. Its apparent clinical benignity may lead to lengthy periods of misdiagnosis, during which it is likely not to spread to distant lymph nodes, but rather to destroy a nose, mandible, or penis as it slowly but relentlessly extends into underlying tissue. Morphologically warty or verrucous, its relatively bland histologic features are often more suggestive of a verruca vulgaris or pseudoepitheliomatous hyperplasia than of squamous cell carcinoma to those unfamiliar with the diagnosis. Alternatively, when it extends into underlying tissues, it may be mistaken histologically for a benign adnexal tumor or even an epidermoid cyst. Therapy may also be challenging because recurrences are common and concerns about potential anaplastic transformation after radiotherapy are often expressed.

Epithelioma cuniculatum (carcinoma cuniculatum) of the thumb: a case report and literature review

Epithelioma cuniculatum is a rare, slow growing, but locally destructive, low-grade epithelioma of squamous cell origin. The first case of this tumor occurring on the thumb is reported. Treatment of this case is discussed, the literature reviewed, and controversy surrounding the naming of this tumor is examined.