The Cytology of Squamous Cell Carcinomas in Domestic Animals

Abstract

Abstract. A series of 40 tumors with a proven diagnosis of squamous cell carcinoma for which both histology and cytology were available were classified according to their histologic appearance as well differentiated, moderately differentiated, and poorly differentiated. The Romanowsky-stained cytology specimens were reviewed. When available, Papanicolaou-stained smears were included. The cytologic findings for each of the 3 groups are described, and the most significant findings are photographically illustrated.Squamous cell carcinomas (SCC) are epithelial tu-1) Well-differentiated tumors: Tumor cells frequently mors commonly arising from the skin 3 or in organs with stratified squamous epithelium, such as tongue, esophagus, pharynx, nasal septum, 17 and uterine cervix.18 Several species can be affected, and at least 3 histologic subtypes can be found in domestic animals: 2 well differentiated, moderately differentiated, and poorly differentiated.17 In 1 series of 555 cutaneous tumors, 33 SCCs were found; 20 were well differentiated, 4 were moderately differentiated, and 9 were 3 poorly differentiated.3 Although there are some publications dealing with the cytologic diagnosis of SCC, 1,5,12,15 the cytology of these tumors has not been thoroughly described, nor has emphasis been placed on the staging of SCC by means of cytology. Cytologic diagnosis has attained an important position in veterinary medicine, and a more detailed study of SCC cells with emphasis in the degree of differentiation is necessary to be able to render a more accurate prognosis based upon cytologic examination. In the present study, the cytology of SCC in domestic animals is described in detail. Materials and methodsA series of 40 histologically proven squamous cell carcinomas from 20 dogs, 7 cats, 7 horses, and 6 cows were selected. The tumors were graded according to their histologic appearance on hematoxylin and eosin (HE)-stained sections as well differentiated (WDSCC), moderately differentiated (MDSCC), and poorly differentiated (PDSCC). The arranged in whorls (pearls) with intensely eosinophilic keratinized centers. Many intercellular bridges throughout the section. Moderately differentiated tumors: Cells frequently arranged in cords or nests; few whorls present, a few of which contained little eosinophilic comified material. Cells with intercellular bridges infrequently seen. Poorly differentiated tumors: Only a few individual cells are keratinizing; cord formation is common. Cells are generally smaller than in other subtypes of SCC.The Romanowsky (Wright)-stained cytology smears of each group were reviewed. When available, Papanicolaou-stained smears were also included. The Papanicolaou staining procedure was modified as recommended by the University of Rochester Medical Center. 8 The methods for the collection of the cytology specimens are shown in Table 1. The most representative cytologic features of all groups were photographed a and are described. ResultsOf the 40 tumors, 17 were WDSCC, 17 were MDSCC, and 6 were PDSCC. Of the...

Impression cytology as diagnostic tool in horses with and without ocular surface disease

“…In our study, equine goblet cells were easily identified with ICS but not with CBS mirroring a previous study where few goblet cells were found with CBS and routine staining [1]. The main focus of equine conjunctival cytology is to detect and classify inflammation in cases with suspected eosinophilic keratoconjunctivitis [19,20] or identify neoplastic cells in cases with suspected adnexal neoplasia [21]. Keratoconjunctivitis sicca is rare in horses [22] and therefore assessment of goblet cells is of less interest in this species.…”

Corneal stromal invasive squamous cell carcinoma: a retrospective morphological description in 10 horses

“…Garma‐Avina mentions cytology as a useful diagnostic tool, but also addresses the risk of misinterpretation. Thus, a differential diagnosis like carcinoma with squamous differentiation and papilloma should be ruled out by biopsy 27 …”

Skin and Subcutaneous Tissues

“…It accounts for 15% of skin tumors in cats but only 2% in dogs (Yager and Wilcock, 1994). A tadpole shape with a tail-like projection and keratinized blue-green hyalinized cytoplasm may be a helpful criterion in determining the cell of origin (Garma-Avina, 1994). Tumors are usually locally invasive and may metastasize to regional lymph nodes.…”