Simeen Ber Rahman  ( Armed Forces Institute of Pathology, Rawalpindi. )
Sajid Mushtaq  ( Armed Forces Institute of Pathology, Rawalpindi. )
Zahid Latif  ( Armed Forces Institute of Pathology, Rawalpindi. )
M. Muzaffar  ( Armed Forces Institute of Pathology, Rawalpindi. )

The reports of Penanal Basal Cell Carcinoma (BCC) are rarely encountered in dermatologic literature. Patients suffering from this relatively less aggressive condition should be differentiated from more sinister neoplasms which may have a similar clinical and histologic presentation. We report two cases of basal cell carcinomas occunng in two unrelated patients.

A 50 year old man reported in a surgical Out patient’s department with a two year history of a slowly growing mass in perineum. The lesion was previously mildly pruritic but recently there was some oozing of blood from the lesion along with slight pain on defaecation. He denied history of any other gastrointestinal symptoms. No investigations were previously done.
On physical examination, an ulcerated mass was seen in the perineumjust above the anal margin. The lesion measured 3x2 cm, had an irregular surface and was partly ulcerated. Clinical impression was of a granulomatous lesion. The patient refused to be photographed.
The biopsied specimen of the lesion showed a tumour mass extending from the epidermis into the dermjs (Figure 1).

The tumour was made up of nests of basiloid cells showing a marginal palisading, cleft-like spaces were seen around the tumour nests. The stroma around the tumour appeared proliferative. The tumour had not been completely removed and was seen to extend up to margins of resection. A histological diagnosis of basal cell carcinoma was made and a wider excision was sqggested.
Case 2
A 45 year old man reported with a history of a swelling in the penanal area for the last 8 months. There was history of oozing and discharge of blood-tinged fluid from the lesion. The lesion was painful and the pain increased on defaecation. There was no history of any other systemic disease. Clinical photograph was not taken.
On physical examination, an eiythematous plaque like lesion, measuring 6x4.5 cm was seen near the right anal margin which was seen extending to the right buttock, it was painful to touch and slight oozing of serous fluid was seen from an erosion on the surface. The clinical impression was that of a squamous cell carcinoma. A biopsy was taken from the margin of the lesion and sent for histopathology.
Histological sections showed nests of basiloid cells extending from the epidermis into the dennis, clefting was seen around the tumour masses (Figure 2).

The stroma was oedematous and proliferative. A mild mononuclear infiltrate was also seen. The tumour was seen to be extending to the lateral and deep margins. A histologic diagnosis of basal cell carcinoma was made and a wide excision was recommended.

Carcinomas may arise fromthe columnarpart of the anal canal epithelium in the form of adenocarcinoma, while the strat:fied columnar epithelial surface may give rise to basiloid colacogenic carcinoma¹. However, the stratified squamous epithelium of the distal anal canal and the adjoining perianal skin can give rise to squamous cell carcinoma and basal cell carcinoma. It is important to differentiate BCC from cloacogenic carcinoma which is an invasive and aggressive tumour and spreads frequently. BCC on the other hand, usually does not recur if completely excised^1,2.
Cloacogemc carcinoma develops from the columnar epithelial cells of the anorectal junction. Other sites include vagina, urethra, sigmoid colon and labial mucosa³. Histologically, the tumour shows basiloid cells with squamoid features as well. There are mitotic figures and the tumour metastasis are frequent^1,3. Perianal BCC, when ulcerated may look like a squamous cell carcinoma clinically, but can be differentiated histologically. Penanal BCC are fifteen fold less common than squamous cell of the same site⁴. Association of perianal BCC with oral squamous carcinoma has been seen withCowden’sdisease³ butourcases did not have any of these associated problem. Pedunculated perianal BCC have also been reported⁵. Although basal cell carcinomas are rare in Blacks, but ma study by Abroco, aperianal BCC hasbeen seen in a young black American⁸.
Another tumour which clinically and histologically is difficult to differentiated is a solitaiy giant trichoepithelioma, which may occur at the same site.
Histologically, this tumour resembles the classical trichoepithelioma of the face, except it is a large sized tumour⁷. Other conditions which clinically can be confused with a perianal BCC are Bowen’s disease, candidiasis, cutaneous amoebiasis and extra mammary Paget’s disease’. Diagnosis may be confirmed histologically.
Perianal BCC are rare tumours but never the less exist and should therefore be excluded in a suspicious perianal lesion. The best form of treatment is a wide excision. The tumour does not recur.

1. Kraus, E.W., Peanal basal cell carcinoma. Arch. Dermatol., 1978;1 17:460-61.
2. Bopana, A., Redondo, P., Idoate, MA. et al. Perianal basal cell carcinoma. Clin. Exp. Dexmatol.. 1992;17:360.362.
3. Vulcan, P., Dumitriu, E. and Grigore, M. Cloacogenic Carcinoma of the lower lip. Ann. Dermatol. Venerol., 1994;1 21:156-158.
4. Augey, F., Cognat, T.. Balmo, B. et al. Perianal basal cell carcinoma. Ann, Dermatol. Venerol., 1994;121:476-478.
5. Kort, R., razza, B., Bouden, S. et al. Perianal basal cell carcinoma. Int. J. Dermatol., 1995;34:427-428.
6. Camisa, C, Bikowski. lB., McDonald, S.G Cowden’s Disease. Association with squamous cell carcinoma of the tongue and perianal basal cell carcinoma. Arch. Dermatol., 1984;120:677-78.
7. Tatnall, F.M. and Jones, E.W. Giant solitary trichoepithelioma located in the perianal area. Br. J. Dermatol., 1986;115:91-99.
8. Abroco, P. and Sanusi, I.D. Basal cell carcinoma in theNorthAmerican Blacks.J. Am. Acad. Dermatol., 1991;6(Pt 1):1005.1011.