More than meets the eye: subretinal aspirate from an acutely blind dog.

A 14-year-old, spayed female Cocker Spaniel was presented to the Boren Veterinary Medical Teaching Hospital at Oklahoma State University with acute loss of vision in the right eye and a history of intermittent bloody diarrhea of unknown duration. Small, white, plaque-like lesions in the retina and subretina were visualized by direct ophthalmic examination, and aspirated with ultrasound-guidance. A direct smear of the subretinal fluid was highly cellular and contained large numbers of pleomorphic organisms consistent with Prototheca sp. The structures were round, oval, or elongated, 4-6 microm width and 8-16 microm in length and surrounded by a thin, clear cell wall. Small, central, pink to purple nuclei were observed in some organisms, but in most, the nuclei were obscured by a deeply basophilic, granular cytoplasm. Some organisms contained endospores. Negatively-stained structures of similar size and shape were considered to be empty casings (theca) of ruptured sporulating and nonsporulating forms of the organism. Protothecosis usually is a disseminated, fatal disease in dogs. The Prototheca organisms observed in this case showed characteristic morphology, illustrating the ability to diagnose protothecosis in cytologic samples.

Draining skin lesion from a desert poodle.

A 16-month-old intact female Poodle in Arizona had a history of intermittent coughing of a few weeks duration. Coccidiomycosis antibody screening test results were negative for immunoglobulin (Ig) M, but were positive (1:64) for IgG. Fine needle aspiration specimens of a draining lesion on the right palmar front foot contained large numbers of neutrophils, many of which contained bacteria, and lower numbers of macrophages. A few small structures also were observed, 2-5 microm in diameter with thin, nonstaining capsules and small, round to oval densely aggregated, eccentric nuclei. Cytologic findings were consistent with septic pyogranulomatous inflammation with Coccidiodes immitis endospores. Fungal culture of a sample from the draining lesion yielded white growth with barrel-shaped arthroconidia. Identification of the organism as C immitis was confirmed by a commercial DNA probe test. Although coccidioidomycosis often is diagnosed by microscopic identification of C immitis spherules in cytologic specimens, in this case only endospores, which are released from mature spherules, were observed. In cases of suspected coccidiodomycosis, the unique morphology of endospores may be useful in making a cytologic diagnosis.

Lymph node cytology.

Lymph node cytology is quick, easy, and rewarding. Cytologic samples of peripheral and/or internal lymph nodes may be collected by fine-needle aspiration biopsy (FNAB) or nonaspiration fine-needle biopsy techniques. In addition, imprints or scrapings may be made from lymph nodes that have been surgically removed or at necropsy. Lymph node cytology is an excellent way to evaluate a lymphadenopathy whether it is a single node enlarged, multiple nodes enlarged, or a generalized lymphadenopathy. If multiple lymph nodes are enlarged, more than one should be sampled. A lymph node away from the mouth or any site of inflammation should be aspirated as well as any lymph node close to a site of inflammation. Generally, if no lymph nodes are enlarged, lymph node cytology is not helpful.

Sample collection and preparation in cytology: increasing diagnostic yield.

Cytology is a valuable diagnostic tool for examining many types of lesions. The diagnostic yield of cytology is dependent on optimal sample collection and smear preparation. This article outlines the basic techniques for collection of samples via fine-needle biopsy, imprints, scrapings, and swabs. Tips are given on how to avoid some of the most common problems that lead to nondiagnostic samples.

Recognition of basic cell types and criteria of malignancy.

In-house examination of cytologic preparations can yield timely information and be done with minimal equipment. This article describes the features that allow for recognition of the basic cell types encountered on cytologic smears. General cellular features suggestive of malignancy are covered as well as some common potential pitfalls in their application. These basic concepts can be applied to samples from each of the specific anatomic locations covered in subsequent articles in this issue.

Carcinoma in the urinary bladder of a cat: cytologic findings and a review of the literature.

Percutaneous fine needle aspiration biopsy (FNAB) was used to diagnose a urinary bladder carcinoma in an aged cat. The cytologic appearance of specimens collected initially was similar to that reported for canine transitional cell carcinoma. However, impression smears of the tumor made at necropsy 7 weeks later consisted predominantly of atypical squamous epithelial cells compatible with squamous cell carcinoma. Histologically, the malignancy was noted to have intermixed areas of abnormal squamous and transitional cell proliferation. The neoplasia was interpreted as a transitional cell carcinoma with extensive transformation to squamous cell carcinoma. This report examines the use and limitations of FNAB in the diagnosis of feline urinary bladder carcinoma and the incidence and behavior of these tumors in the cat.