Indian Journal of Dermatology
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Year : 2005  |  Volume : 50  |  Issue : 4  |  Page : 216-220
Carcinoma cuniculatum at various anatomical sites

Department of Pathology, Government Medical College, Nagpur, India

Correspondence Address:
Mrunamayi Kotwal
Govt. Medical College, Nagpur
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Carcinoma cuniculatum, a low grade squamous carcinoma of plantar skin was first described in 1954. Even after 50 years, biopsy errors are common with delay in diagnosis. Clinico-morphologica1 features in 12 patients of carcinoma cuniculatum, in a period of three and a half years are studied. The aim is to draw attention to the sites of occurrence of this tumor other than the sole and to have better understanding of the diagnostic difficulties. The sites of occurrence of these tumors according to frequency were foot followed by flank, leg, face and palm. The tumors presented with ulcerated, fungating masses with fine papillary architecture. Microscopic examination of the tumors revealed bulbous acanthosis, parakeratosis and a well defined lower border, circumscribed by chronic inflammatory cells. No lymph node metastasis were recorded in any of the cases. Wide local excision with at least five mm free surgical margin was the treatment of choice. A transmetatarsal and above wrist amputation was required in two patients. Carcinoma cuniculatum should always be suspected in a nonhealing ulcer or verrucous growth of long standing duration. Superficial and small biopsies are unsatisfactory. Benign appearance on histopathology of this tumor needs to be interpreted in proper clinical settings.

Keywords: Verrucous carcinoma, Squamous cell carcinoma, Carcinoma cuniculatum

How to cite this article:
Kotwal M, Poflee S, Bobhate S. Carcinoma cuniculatum at various anatomical sites. Indian J Dermatol 2005;50:216-20

How to cite this URL:
Kotwal M, Poflee S, Bobhate S. Carcinoma cuniculatum at various anatomical sites. Indian J Dermatol [serial online] 2005 [cited 2022 Jan 25];50:216-20. Available from:

   Introduction Top

Carcinoma cuniculatum or verrucous carcinoma of skin, a rare variant of low grade squamous cell carcinoma was first described as epithelioma cuniculatum by Aird and associates in 1954.[1] There are only few large series reporting on this tumor, rest are only in the form of case reports. [2],[3],[4],[5],[6],[7]

The tumors are mostly described on the sole of the foot, although they have been infrequently reported to occur elsewhere on the skin at sites of long standing scars. Problems arise in diagnosing the disease because of the protracted growth and the benign appearance of the tumor.

Here is a report of series of 12 cases of carcinoma cuniculatum. To the best of our knowledge this is a first report of series from India.

The purpose of this study is to present clinical features and light microscopic findings in 12 patients in order to understand this entity better.

Our purpose is also to draw attention of the clinicians and pathologists to the occurrence of this distinct tumor at the sites other than plantar aspect of foot.

The diagnostic difficulties and differential diagnoses are also discussed.

   Materials and methods Top

The study comprises of 12 cases of carcinoma cuniculatum diagnosed at the department of pathology, Government Medical College, Nagpur from January 2000 to June 2003.

Clinical data regarding age, sex, predisposing factors, duration of lesion, site and size of tumor and lymph node status was recorded in the patients admitted in the surgical wards. Diagnostic biopsy was performed in 11 out of 12 patients. In two of these cases biopsy was repeated twice and thrice to confirm the diagnosis. After the diagnosis, wide local excision was done and the tumor was sent for histopathological study. The routine hematoxylin and eosin (H&E) stained sections were studied.

   Results Top

The clinical data of the patients is listed in [Table 1] Patients ranged in age from 32 to 70 years. Only one patient was below the age of 40 years. Over 90% of the patients were between 50 and 70 years of age. Men outnumbered the females by a ratio of 5: 1.

Common clinical findings include a non-healing ulcer and an exophytic growth. The sites of occurrence of these tumors according to frequency were foot (plantar aspect)- 4, flank- 3, leg- 2, face- 2 and palm- 1.

There was a history of trauma, thorn prick, application of some medicine and chronic scarring. None of the cases had a history of leprosy. In one case there was a history of recurrence, the previous operation being done outside the institute.

Macroscopic findings: The tumors ranged in size from 1 to 12 cm. There was an ulcerative or cauliflower like growth protruding above the surface of skin with thick, white keratinisation over the surface [Figure l][Figure - 2]. Cut section revealed classical fine papillary architecture.

Microscopic features: These tumors showed a classical exo and endophytic growth pattern with undulating papillomatosis. The down growths of the tumor were club shaped and had a very distinct line of invasion into deeper tissue with an intact basement membrane and a single basal layer. The verrucous surface revealed cleft like spaces covered by parakeratinised cells extending deep into the lesion [Figure - 3]. Cellular atypia, mitotic activity or other characteristics of malignancy were characteristically absent. The keratinocytes appeared to stain lightly with eosin and possessed a small nucleus. Deeper tissue invariably revealed numerous inflammatory cells, mainly lymphocytes beneath the tumor. Collagen appeared to be compressed at the lower margin of the tumor.

Lymph nodes- In ten patients no lymph nodes were palpable. In two of them the lymph nodes were mobile and showed sinus histiocytosis and no metastasis.

   Treatment Top

In ten patients wide local excision was done with a free margin of at least 5 mm. In one case of recurrence a transmetatarsal amputation was done. At the time of previous operation, three year back, patient had lost two toes. The growth had now became extensive and was extending from ventral to dorsal aspect of foot. In another case an above wrist amputation was done due to very large size of the tumor. Radiation therapy was not received by any of our patients.

   Discussion Top

Verrucous carcinoma is a low grade squmous cell carcinoma, first described by Ackerman in the oral cavity.[8]

Three major forms are recognized, all of them occurring in areas of maceration. Most common form occurs in oral cavity. It is also seen in larynx, nasal cavity and esophagus. Second form is seen in anogenital region. Third is plantar verrucous carcinoma called as carcinoma cuniculatum, which at first shows a striking resemblance to an intractable plantar wart. As the exophytic mass grows it shows a great tendency towards deep, penetrating growth resulting in numerous deep crypts filled with horny material and pus. The crypts resemble the burrows of rabbits, hence the name carcinoma cuniculatum. The tumor ultimately penetrates the plantar fascia and may even destroy metatarsal bones and invade the skin of the dorsum of foot. Apart from classical site, verrucous carcinoma of skin has been described at many other areas, such as face and back, as well as over preexisting lesions such as chronic ulcers and draining sinuses e.g. hidradenitis suppurativa.[9] In the present report 12 cases of verrucous carcinoma of skin are recorded in a period of three and a half years. The site wise distribution of cases was plantar aspect of foot-four, flank-three, leg-two, face- two and palm- one.

All the cases had classical clinical and morphological features.

Various etiological factors were implicated in these cases. History of trauma, thorn prick, chronic application of some medicine and chronic scarring due to wearing tight dhoti or saree. Others have described occurrence of this tumor in chronic ulcers in leprosy and diabetis mellitus.[2],[3]

A possible viral origin has been suggested because of a close relationship with plantar warts. However Kao et al could not demonstrate Human papilloma virus (HPV) antigen using the immunoperoxidase technique.[2] Noel JC et al demonstrated HPV type 2 DNA in a case of verrucous carcinoma of foot, by PCR.[10] Schell BJ et al recently identified HPV type 16 in episomal and integrated forms in two cases of plantar verrucous carcinoma by PCR. Also demonstrated were the alterations of c-Ki-ras, p53, and Rb genes.[11]

Histologically, the diagnosis of verrucous carcinoma is usually difficult largely as a result of cellular features of a benign tumor. The superficial biopsies are often reported as hyperkeratosis, acanthosis, benign squamous papilloma and mild dysplasia. In two of our cases this difficulty was encountered and diagnosis was reached after repeated biopsies. Thus the final diagnosis is not based on the cytological features alone but on the clinical, macroscopic and microscopic architectural features.

Differential diagnoses include viral warts, keratoacanthoma, and pseudocarcinomatous (pseudo epitheliomatous) hyperplasia.[5],[7]

Classical verrucous carcinoma is a well demarcated exophytic whitish growth showing fine papillary architecture on cut section. Microscopically it shows an exophytic and endophytic proliferation of well differentiated squamous epithelium. It also shows a more pronounced hyper and parakeratinisation in the downward extensions, which appear bulbous rather than sharply pointed. It runs a protracted course.

In contrast, viral warts and condylomata acuminata do not show endophytic zones and show keratohyline granules. They do not usually grow over many years, having a tendency toward spontaneous regression.

Keratoacanthoma is never verrucous in appearance and has a rapid self limited and self healing course. Microscopically it shows a large crater filled with keratin. There is an upward and downward proliferation of epithelium from the crater. Individual cell keratinisation and horn pearl are also seen. However solitary keratoacanthoma almost never affects the palms and soles.

Pseudocarcinomatous hyperplasia is a reactive process to a causative factor. It rarely causes difficulty in distinguishing it from verrucous carcinoma. It shows irregular invasion of the dermis by uneven, jagged, often sharply pointed epidermal masses and strands which are well differentiated.

In our patients excision of growth with free surgical margins of 5 mm was the treatment offered. In two patients a transmetatarsal and above wrist amputation was done due to extensive growth.

   Conclusions: Top

Carcinoma cuniculatum is a distinct clinical entity. It should be suspected whenever there is a non-healing ulcer or a verrucous growth of long standing duration. Though plantar skin is the most common site of occurrence, it can occur at other locations with chronic scarring. Superficial and small biopsies are always unsatisfactory. Therefore biopsy of the lesion should be large, deep and should also include normal skin on one side.

Wide local excision with at least five mm free margin is the treatment of choice.

   References Top

1.Aird I, Johnson HD, Lennox B, Stansfeld AG. Epithelioma cuniculatum : a variety of squamous carcinoma peculiar to the foor. Br J Surg 1954; 42: 245-50.   Back to cited text no. 1  [PUBMED]  
2.Kao GF, Graham JH, Helwig EB. carcinoma cuniculalum (verrucous carcinoma of the skin): a clinicopathologic study of 46 cases with ultrastructural observations. Cancer 1982; 40: 2395-2403.   Back to cited text no. 2    
3.Mckee PH, Wilkinson JD, Black MM, Whimster JW. Carcinoma (epithelioma) cuniculalum: clinicopathological study of nineteen cases and review of literature. Histopathology 1981; 5(4):425-36.   Back to cited text no. 3    
4.Job CK, Reidel RG. Squamous cell carcinoma arising in plantar ulcers in leprosy. Ind J Leprosy 1964; 32: 3744.   Back to cited text no. 4    
5.Brownstein MH, Shapiro Lewis. Verrucous carcinoma of skin, epithelioma cuniculatum plantare. Cancer 1976;38: 1710-6.   Back to cited text no. 5    
6.Prioleau PG, Santa Cruz DJ, Meyer JS, Bauer WC. Verrucoua Carcinoma: a Light and electron microscopic, autoradiographic, and immuno fluorescence study. Cancer 1980; 45: 2849-57.   Back to cited text no. 6  [PUBMED]  
7.Vandeweyer E, Sales F, Deraemaecker R Cutaneous verrucous carcinoma. Br J Plastic Surg 2001; 54: 168-70.   Back to cited text no. 7    
8.Ackenuan LV. verrucous can:inoma of the oral cavity. Surgery 1948; 23: 670-8.   Back to cited text no. 8    
9.Kirkham N. Tumors and cysts of the epidermis. In: David E. eds. Lever's Histopathology of skin. 8th ed. Philadelphia: New York. Lippincott Raven publishers, 1997: 716-17.   Back to cited text no. 9    
10. Noel JC, Peny MO, Detremmerie O, et al. Demonstration of human papillomavirus type2 in a verrucous carcinoma of the foot. Dermatology 1993;187(1):58-61.   Back to cited text no. 10    
11.Schell BJ, Rosen T, Rady P, et al. Verrucous carcinoma of the foot associated with human papillomavirustype 16, J Am Acad Dermatol 2001; 45(1): 49-55.   Back to cited text no. 11    


[Figure - 1], [Figure - 2], [Figure - 3]


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