Multicentric Squamous Cell Carcinoma in situ Resembling Bowen's Disease in Cats

Abstract

Multicentric squamous cell carcinoma in situ was studied in 12 cats (eight castrated males and four spayed females). The neoplasms occurred in middle-aged to old (mean age = 12 years) mixed-breed cats with a variety of hair-coat colors. The lesions were found in haired pigmented regions of the skin, including the trunk, limbs, feet, head, and neck, and were unrelated to exposure to sunlight. Lesions occurred at multiple sites in nine cats and at solitary sites in three cats and were from 0.5 cm to 3.0 cm in diameter, irregular, slightly elevated, plaque-like or papillated, and partially alopecic. Histologically, the lesions consisted of sharply demarcated regions of neoplastic, keratinocytic infiltration of the epidermal and follicular infundibular epithelium. Neoplastic cells were confined to the epithelium without frank invasion of the dermis. Two histologic subclasses of multicentric squamous cell carcinoma in situ were identified, the irregular nonhyperkeratotic type and the verrucous hyperkeratotic type. Three cats also had invasive squamous cell carcinoma adjacent to lesions characteristic of multicentric squamous cell carcinoma in situ. Grossly, these were solitary 2.0-4.0 cm-diameter firm, crusted, crateriform cutaneous masses. During follow-up periods of 4 to 20 months (mean follow-up period = 11 months), neoplasms did not recur locally after surgical excision; however, similar lesions developed at new sites in four cats.(ABSTRACT TRUNCATED AT 250 WORDS)

Squamous cell carcinoma (Bowen’s disease) in situ in three cats

“…The primary macular lesions, typical of BD (Scott et al, 2001), were not noted by the owners. The cats already had hyperkeratotic, hyperpigmented and crusted plaques, similar to the typical chronic lesions of BD (Miller et al, 1992;Baer and Helton, 1993). Cutaneous horns, reported in some lesions (Rees and Goldschmidt, 1998), were not found in the cats.…”

“…Cutaneous horns, reported in some lesions (Rees and Goldschmidt, 1998), were not found in the cats. Usually, BD lesions in cats are multicentric and affect most frequently the cephalic, cervical and thoracolumbar areas, as well as the forelimbs (Miller et al, 1992;Baer and Helton, 1993). Cases 2 and 3 cats had a multicentric pattern of distribution, but the case 1 cat showed a single lesion on its left preauricular area.…”

“…Cases 2 and 3 cats had a multicentric pattern of distribution, but the case 1 cat showed a single lesion on its left preauricular area. There are also reports of single BD lesions in cats, basically limited to the ventral portion of its neck, lateralthorax and medial region of hindlimbs (Baer and Helton, 1993). The major differential diagnosis of BD in cats is actinic keratosis.…”

“…The major differential diagnosis of BD in cats is actinic keratosis. Histologically, actinic keratosis may affect the infundibulum of hair follicles (Baer and Helton, 1993), but in a lesser extend than BD. Furthermore, actinic keratosis may show color changes, alternating dark and light epidermal shades.…”

“…Furthermore, actinic keratosis may show color changes, alternating dark and light epidermal shades. In cats, as well as in man, BD and Bowenoid actinic keratosis are histologically indistinguishable (Baer and Helton, 1993). In man, these diseases are differentiated by size; usually the lesions of actinic keratosis are smaller than the lesions of BD (Kirkham, 1997).…”