Exfoliative dermatitis with thymoma

14 Exfoliative dermatitis with thymoma




INITIAL PRESENTATION


Scaling, crusting, erythema and alopecia.



INTRODUCTION


Exfoliative dermatitis has been described in association with thymoma, both in people and in cats. A number of well-recognized paraneoplastic syndromes, such as cachexia, leucocytosis, hypercalcaemia and hyperglycaemia, are due to the systemic effects of hormones and/or other factors produced by the tumour, or its metastases, rather than the direct effect of the neoplastic invasion itself. In rare cases paraneoplastic signs such as exfoliative dermatitis, erythema multiforme, myasthenia gravis, myositis and myocarditis have been associated with thymoma.


In some of these cases, the paraneoplastic syndrome can be more life threatening than the tumour. Early recognition of such syndromes and appropriate treatment can lead to resolution of the clinical signs, and improve the quality of life and the survival time of the patient. This chapter describes the cutaneous clinical presentation in a cat with a thymoma.




CASE PRESENTING SIGNS


An 8-year-old, spayed British short-haired cat, weighing 3.35 kg, from a multi-cat household, was referred with a history of a severe exfoliative and crusting dermatitis.



CASE HISTORY


Most cats with thymoma present with a history of dyspnoea, coughing, lethargy and anorexia, which are often associated with the presence of a large space-occupying mass in the cranial mediastinum. The onset of cutaneous signs is usually sudden, with no previous history of dermatological disease. As most affected cats are old, owners often relate some of the signs, such as lethargy or changed demeanour, to age. The appetite in most cases is unaffected.


The relevant history in this case was:


• The cat’s general health had been unaffected.

• The cat was reported to have a normal appetite and was fed on a variety of proprietary diets.

• The onset of dermatological signs was sudden and only 3 weeks before presentation.

• The initial signs were non-pruritic profuse scaling and crusting on the dorsum and mild bilateral conjunctivitis.

• Skin scrapings and fungal culture were negative for ectoparasites and dermatophytes.

• There was no history of a cough or any other respiratory signs.

• Trial treatments with selamectin and chloramphenicol eye ointment were prescribed.

• The condition did not appear to be contagious to the other cats in the household, or zoonotic.


CLINICAL EXAMINATION


This condition is characterized by moderate to severe exfoliation, erythema and alopecia, affecting mainly the face and the pinnae. The lesions may progress to the dorsum and the legs, and may eventually involve the whole body. Secondary bacterial and Malassezia infections can further complicate the disease.


The relevant findings of a physical and dermatological examination were:


• The body and coat condition were poor (Fig. 14.1).

• The heart rate was 130 beats per minute, temperature 39.5ºC and bilateral thoracic auscultation was unremarkable. The peripheral lymph nodes were marginally enlarged.

• Oral examination revealed a small lingual ulcer, dental calculus and plaque.

• The hair was easily epilated.

• There was generalized erythema with crusting and scaling on the trunk (Fig. 14.2).

• Alopecia, erythema, focal crusting, comedones, hyperpigmentation and a brown waxy exudate were evident on the perianal area, extending to the ventral aspects of the abdomen and the medial aspects of the thighs (Fig. 14.3).

• There was scaling and crusting on the medial aspect of the elbows (Fig. 14.4).

• Mild scaling was evident on the pads of all four feet (Fig. 14.5).

image

Figure 14.1 Poor body and coat condition.


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Figure 14.2 Crusting, scaling and hypotrichosis on the dorsum.

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Sep 3, 2016 | Posted by in SMALL ANIMAL | Comments Off on Exfoliative dermatitis with thymoma

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