Epitheliotropic T Cell Lymphoma in a Terrier Mix Dog

Phoolish presented for a 3 month history of progressive hair loss, crusting and pruritus (itch) directed to the face and paw pads.  No improvement following two courses of antibiotics and perceivably worse after starting thyroid supplementation (levothyroxine). 

Christie Yamazaki DVM, DACVD

Dermatology For Animals, Oakland, CA

 

SUBJECTIVE

Phoolish is a 12 yr 7 month old MC Terrier Mix with a multi-year history of hair loss, crusting and tremendous itch directed to the chest and paws initially, progressing to the face and paw pads perceivably after starting levothyroxine 3 months prior.  Multiple courses of antibiotics (cephalexin, clindamycin) were ineffective at decreasing the crusting.  He was obtained as a puppy, and had been under the care of a veterinary dermatologist since he was 1.5 yr of age with allergen-specific immunotherapy and periodic Apoquel® and Cytopoint® to treat generalized seasonal itchiness.  He used to dig in the back yard where he was bit by a copperhead snake 1 yr prior.

 

OBJECTIVE

Weight: 6.5 kg (14.3 lb)

Temp: 101.3 F (rectal)

Pulse: 130 bpm

Resp: 24 bpm

 

Dermatologic physical examination: QARH, BCS 4/9. Phoolish was very sweet and easily examined. The periocular skin had erosions bilaterally.  There was bilateral pinnal hemorrhagic crusts.  Marked firm erythematous plaques over the dorsal muzzle with alopecia and crusting. Hypopigmentation, erosions and loss of cobblestone texture was noted to the nasal planum.  Hypopigmentation and erosions were noted to the rostral muzzle.  All paws had alopecia and erythema of the dorsal metacarpals and metatarsals as well as claw folds.  The paw pad surfaces were smooth  and hypopigmented. Alopecia, moist exudate and erythema was present at the interdigital, palmar and plantar skin. Patchy hypotrichosis of the dorsal trunk, flanks, axillae, ventral chest, proximal limbs and tail with reticulated hyperpigmentation and lichenification. All lymph nodes palpated symmetric with no obvious lymphadenomegaly.

 

Differential diagnoses included epitheliotropic T-cell lymphoma (cutaneous lymphoma), pemphigus foliaceus, dermatophytosis, and erythema multiforme.

 

DIAGNOSTICS

Skin cytology of the palmar skin revealed TNTC intracellular and extracellular coccoid-shaped bacteria, lower numbers of rod-shaped bacteria, abundant polymorphonuclear cells.   Skin cytology of the dorsal muzzle revealed 3-10 coccoid-shaped bacteria/oil immersion field. A deep skin scrape revealed no mites or ova.  Phoolish received mild reversible sedation via dexmedetomidine (Dexdomitor™) in addition to butorphanol (Torbugesic™) IV. Five sites were selected and locally blocked with a lidocaine-saline solution, and submitted for both tissue culture and dermatohistopathology.

 

ASSESSMENT

The biopsy results revealed crusted parakeratotic, focally eroded epidermis with colonies of bacteria.  All samples exhibited epitheliotropic infiltrate with large, atypical lymphocytes.  In some sections were was extension of the atypical lymphoid cells into the mid to deep dermis with focal nodules.  Pautrier microabscess formation (focal accumulations of atypical lymphocytes in the epidermis) was present with dermal infiltrate exhibiting a band-like pattern that extended from the superficial dermis to the adnexa, invading some mural portions of the hair follicles.  There was a high mitotic rate with four to five mitoses per high-powdered field.  These findings were consistent epitheliotropic T-cell (cutaneous) lymphoma – plaque to tumor stage.

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