Cytochemical detection of calcium in a case of calcinosis circumscripta in a dog

Silica and barium: Comparison of microscopic appearance and characterization of effects of silica on cytomorphology

BACKGROUND

Silica from plastic red top sample collection tubes and barium cause recognized artifacts in slide preparations for microscopic examination.

OBJECTIVES

The objectives of this study were to evaluate and directly compare the microscopic appearance of silica and barium particles and various slide preparation techniques (e.g., use of coverslips, oil immersion, and different stains). A secondary objective of this study was to evaluate the effects of silica particles on cellular morphology after mechanical trauma with cytocentrifugation.

METHODS

Fluid samples (deionized water, pleural effusion, peritoneal effusion, cerebrospinal fluid, and urine) were collected and evaluated in silica- and non-silica-containing tubes. Barium was added to silica and non-silica samples. Direct and cytocentrifuge preparations were compared to evaluate the effect of silica particles on cellular morphology. Preparations were stained with Wright-Giemsa, rhodizonic acid disodium salt, Alizarin Red, Grocott's methenamine silver, and Prussian blue.

RESULTS

Silica and barium particles were identifiable via light microscopy with and without polarized light, although silica particles diminished with immersion oil. Barium particles retained their structure and diminished less under oil. Cytoseal mounting medium for coverslip placement resulted in diminished refractility of silica and some barium particles. Silica particles with mechanical interaction during cytocentrifugation resulted in disrupted cellular morphology with many lysed cells. Silica and barium particles were negative for all special stains tested.

CONCLUSIONS

Silica from plastic red top tubes adversely affects cell morphology in cytocentrifuge preparations, potentially affecting manual differential cell counts and compromising diagnostic interpretation. Samples intended for microscopic evaluation should not be collected in silica-containing tubes.

Imaging diagnosis: Multiple cartilaginous exostoses and calcinosis circumscripta occurring simultaneously in the cervical spine of a dog

An 8-month-old female Saint Bernard dog was presented with gait abnormalities consistent with a left-lateralizing cervical myelopathy. Imaging revealed a large, irregular soft tissue and mineral mass at the level of C1 and C2. The lesion was successfully excised, and histopathology was performed, revealing evidence of both multiple cartilaginous exostoses and calcinosis circumscripta. To the authors' knowledge, this is the first report comparing features using magnetic resonance imaging, computed tomography, and radiography. Additionally, multiple cartilaginous exostoses have not previously been reported to occur in combination with calcinosis circumscripta.

Metastatic calcinosis (including calcinosis cutis) in a young dog with multiple urinary tract abnormalities

Metastatic calcinosis associated with chronic renal failure and multiple urinary tract abnormalities was diagnosed in a 6-month-old Brittany spaniel that was presented with calcinosis cutis. This case report highlights the importance of skin as an indicator of systemic disease. The aetiopathogenesis of the four main types of tissue calcification is defined and discussed with an emphasis on metastatic calcinosis.

Bilateral dystrophic calcinosis circumscripta in a cynomolgus macaque (Macaca fascicularis)

The authors describe a case in which well-circumscribed, expansile, and nonencapsulated nodular masses with missing digits were detected on the right and left feet in a 6-year-old female cynomolgus macaque from a routine toxicology study. Grossly, these masses were composed of variably sized and firm nodules containing white, chalklike material in the subcutaneous tissue on cross section. Microscopically, the nodules were composed of irregular lobules containing amorphous to granular, light to dark basophilic material that was surrounded by macrophages and multinucleated giant cells and separated by fibrous connective tissue. The nodule's contents were von Kossa and Alizarin red S positive. Serum calcium and phosphorus levels of this monkey were within normal ranges. Based on the gross pathology, histopathology, serum chemistry, and histochemistry, a diagnosis of dystrophic calcinosis circumscripta was made. Dystrophic calcinosis circumscripta is an uncommon syndrome of mineralization that occurs following tissue damage, without abnormalities in calcium and phosphorus homeostasis, and it is characterized by deposition of calcium salts in soft tissues. To the best of the authors' knowledge, this is the first report of dystrophic calcinosis circumscripta in a cynomolgus macaque.

Use of destained cytology slides for the application of routine special stains

BACKGROUND

Special stains to demonstrate microorganisms or intra- and extracellular substances have not been evaluated in detail regarding their applicability and usefulness in destained cytologic specimens.

OBJECTIVES

The aim of this study is to compare the results of routine special stains on destained slides previously stained with Hemacolor and on fresh (unstained) specimens.

METHODS

Archival Hemacolor-stained fine needle aspirate specimens of inflammation with infectious agents (bacterial, mycobacterial, and fungal infections), neoplasia (melanoma, myxosarcoma, and mammary adenocarcinoma), and hemorrhage (pericardial effusion) from 14 dogs and 7 cats were selected. Cells in a minimum of 4 fields were photographed and 5 slides from each case were then destained by different methods (alcohol acid or microwave). Seven special stains were applied selectively to the destained slides, depending on the cytologic findings: periodic acid Schiff, Grocott-Gomori methenamine silver, Gram's, Ziehl-Neelsen, Alcian blue, Fontana-Masson, and Prussian blue. The same fields were rephotographed and 2 observers evaluated the slides qualitatively, with comparison to fresh cytologic specimens from similar lesions.

RESULTS

Special stains applied to destained slides demonstrated the expected cellular and extracellular material or organisms independent of the destaining method. Staining intensity, nonspecific staining (background), cell morphology, and nuclear counterstaining results were similar to those of special stains applied to fresh unstained slides.

CONCLUSIONS

Destaining does not appear to affect the results of routine special staining for cytologic specimens. Destaining before special stains may be a valuable diagnostic strategy when few slides are present or only stained slides are available.