Feline injection site‐associated sarcomas

Sarcoma felino posvacunal (FISS), reporte de caso en Colombia

El sarcoma felino posvacunal o sarcoma de sitio de inyección (FISS) en una neoplasia poco descrita en felinos en Colombia, se presenta posterior al uso de vacunas inactivas con adyuvante. El objetivo fue describir la presencia de un sarcoma felino posterior a la vacunación con leucemia felina virus inactivo, primer caso documentado en Colombia. Un felino, macho, mestizo, de 7 años de edad, esterilizado, vacunado con leucemia felina inactiva desde hace 3 años, desarrolla un nódulo de 5 cm de diámetro en la región dorsal, firme y no doloroso. En dermis profunda y músculo estriado, se evidencia proliferación neoplásica de células fusiformes, de crecimiento principalmente expansivo y en menor medida invasivo, que se organiza y forma haces cortos y fascículos largos que se entrecruzan, con focos densos y laxos y en focos se dispone en un patrón de espina de pescado. Las células presentan morfología fusiforme, ligeramente ovoide, irregular, algunas redondeadas, con citoplasma eosinófilo tenue e intenso en otros focos más densos. Se evidencia pleomorfismo celular y anisocitosis moderadas. Los núcleos presentan morfología redonda, ovoide e irregular. Se evidencia la presencia de uno o más nucléolos en algunas de sus células, cromatina principalmente granular fina, pleomorfismo nuclear y anisocariosis moderada. Se contabilizaron 4 mitosis en 10 campos con el objetivo de alto poder en 2,37 mm2, no se observa aparente invasión linfovascular, se evidencia compromiso de bordes laterales. Adicionalmente, discretos focos de necrosis multifocal < 50%, infiltrado inflamatorio mixto polimorfonuclear, neutrófilos moderados multifocales e infiltrado mononuclear linfocítico multifocal.

Thermographic assessment of skin and soft tissue tumors in cats

OBJECTIVES

This study set out to determine the average temperature of skin and soft tissue tumors in cats using infrared thermography and to investigate correlations between thermographic findings and tumor type. Correlations between thermographic findings, histologic subtype and tumor grade were also investigated in cases of feline injection site sarcoma (FISS).

METHODS

Thermographic images of normal skin and skin overlying neoplastic lesions were prospectively obtained. Following thermographic assessment, tumors were resected and submitted to histopathologic and immunohistochemical analysis. Mean temperatures detected in tumoral areas were compared between different tumor types and between FISSs of different histologic subtypes and grades.

RESULTS

Thermograms obtained from 11 healthy cats and 31 cats presenting with skin and soft tissue tumors (eight benign and 23 malignant tumors, including 21 FISSs) were evaluated in this study. Thermal behavior varied widely in normal skin, as well as in skin overlying neoplastic lesions. Mean temperatures were significantly higher in malignant compared with benign tumors (35.4 ± 1.8ºC and 34.5 ± 1.7ºC respectively; P = 0.01), with a temperature above 34.7ºC being associated with malignancy (sensitivity 76%, specificity 80%; P = 0.01). Temperatures detected in FISS did not differ significantly according to histologic subtype (P = 0.91) or tumor grade (P = 0.46), or between primary and recurring tumors (P = 0.25).

CONCLUSIONS AND RELEVANCE

Infrared thermography proved to be a sensitive and effective method for detection of temperature differences between malignant and benign skin and soft tissue tumors in cats. Thermographic assessment may contribute to diagnosis and prognostic estimation in feline oncologic patients.