Introduction

Multicentric squamous cell carcinoma in situ (MSCCIS), known as Bowen-like disease or multiple Bowenoid in situ carcinoma, is a rare skin disease. Its pathogenesis is generally associated with papillomavirus infection. The papillomavirus shows skin tropism and persistent infection in a basal cell layer. Hence, large or multiple spread lesions are difficult to be cured by surgical excision. Zinc chloride paste (Mohs paste) is a topical fixative used for palliative treatment for accessible skin tumors. We reported for the first time two successful cases of modified Mohs paste treatment (mMPT) for a dog and cat with MSCCIS.

Methods: In Case 1, a 12-year-old, spayed female domestic cat showed erosions, ulcers, and bleedings around paw pads of all feet and ventral antebrachial region of the left paw. mMPT had been repeated over once a weekly to monthly without anesthesia. In Case 2, a 7-year-old, spayed female Norfolk terrier showed multiple pigmented macules and nodules at the back of the neck skin for 9 months. mMTP was repeated once per week.

Results

In Case 1, the ventral antebrachial lesions were cured and progression around the paw pads was prevented by continuous mMPT. In Case 2, the nodules became cutaneous ulceration, whereas the open wound was closed by epithelialization. The survival times were 514 days (Case 1) and 1043 days (Case 2) after the first mMPT. The side effect included mild pain during uniform application of the paste.

Conclusion

In both cases, mMPT was useful for prevention of MSCCIS progression and increasing the patients’ quality of life.