Cytological examination of skin in dogs

One method of veterinary diagnostics is cytological examination of blood, mucous membrane tissue, tumors, or skin. The name of this method comes from the Latin word "cytos," meaning cell, since, unlike histological examination, which studies the general structure and function of tissues, cytology examines cellular structures.

During a cytological analysis, the structural features of cells are examined using a microscope: appearance, shape, size, color, and the presence of foreign inclusions. This simple and minimally invasive method allows for the detection of abnormalities in cell structure and function.

Content

1 When is skin cytology prescribed?
2 Methodology of analysis

When is skin cytology prescribed?

Cytological examination of a dog's skin can detect neoplastic (atypical), infiltrating (inflammatory) and bacterial cells, parasitic organisms, and fungi.

Please note! The word "Cito!" written on a referral form for any test has nothing to do with cytology; it means the test needs to be performed urgently.

Indications for cytological analysis of skin in dogs are:

papular or pustular rash;
skin itching of unknown etiology;
alopecia (hair loss or its uneven growth);
formation of crusts or scales on the skin;
nodular or tumorous neoplasms localized in the dermis;
changes in skin pigmentation.

Useful information! Many skin diseases produce similar clinical presentations. Skin cytology examinations allow us to differentiate symptoms and diagnose dermatitis. bacterial pyoderma, parasitic skin diseases, benign and malignant neoplasms.

Methodology of analysis

The most commonly used sampling technique for cytological analysis is skin scraping, or, if the tissue sample is from a skin lesion or papule, fine-needle aspiration.

To obtain a skin scraping, you will need a sterile disposable scalpel or curette (a surgical instrument in the form of a spoon or ring with sharp edges), a microscope with slides, and mineral oil (a biologically neutral liquid obtained from petroleum) to wet the scalpel or curette.

A superficial skin scraping is performed without anesthesia. Before performing a deep skin scraping on a dog, a veterinarian may treat the desired area of skin with a local anesthetic. Chloroethyl aerosol is most often used for this purpose, which “freezes” the dermal tissue for several minutes.

When performing a deep scraping, a scalpel or curette is inserted into the skin until blood appears from the superficial capillaries. The resulting material, along with a drop of mineral oil, is then applied to a glass slide and covered with a coverslip. The material is visually examined under a microscope, first using low magnification (100x) and then high magnification (1,000x).

In some cases, cystoscopy requires fixation of the sample on a glass slide with alcohol or formalin. To detect structurally abnormal cells, the sample is stained with special dyes that serve as markers for atypical cells. Papanicolaou staining can detect malignant cells and viruses, while Romanovsky staining is effective in detecting bacteria and fungi.

When examining the biomaterial, the cell structure and shape are assessed to determine whether they correspond to normal values. Cytoplasmic features, nuclear changes, and the presence or absence of abnormal inclusions are examined. Any deviations from the norm are documented by the laboratory technician on a special form.

A specialist interprets the cytological analysis; all data is entered into the report form using the Bethesda abbreviation, which is commonly used in medical terminology and understandable only to doctors.

The advantage of skin cytology in dogs is that the test is quick and easy to perform, and its results either provide the information needed to establish an accurate diagnosis or clearly indicate the direction of further diagnostic investigation. Cytology is also effective as a method for interim evaluation of treatment results.