Chemotherapy for dogs with lymph node metastasis from histiocytic sarcomas.

BACKGROUND: Histiocytic sarcomas (HS) frequently metastasise, most commonly to visceral sites, but also to regional lymph nodes. Nodal metastases are associated with a poorer prognosis. This retrospective study aimed to evaluate prognostic factors, including the effect of adjuvant chemotherapy, on survival in dogs with nodal, but not systemic, metastases from HS. METHODS: Retrospective case series of 12 dogs with histologically diagnosed HS metastatic to lymph nodes treated with surgery with and without adjuvant chemotherapy. RESULTS: All dogs had histological evidence of metastasis to lymph nodes, with no clinical evidence for metastasis to viscera. Eight dogs that received chemotherapy had a median estimated survival of 219 days (range 77-1638 days); 1- and 2-year estimated survival rates were 37.7%. Median survival time for 4 dogs with nodal metastases that did not receive chemotherapy was 57 days (range 39-136 days) with none alive 1 year after surgery CONCLUSION: Survival for dogs with only regional nodal metastases from HS appeared to be improved by adjuvant chemotherapy.

Autochthonous feline leprosy caused by Mycobacterium sp. strain Tarwin affecting a cat from the Central Coast of New South Wales.

CASE REPORT: A 5-year-old Domestic Shorthair-cross was presented with a raised, alopecic skin nodule affecting the external surface of the right upper lip with an adjacent second smaller satellite lesion. Fine needle aspiration cytology revealed numerous intracellular and extracellular negatively stained bacilli. Histopathology confirmed granulomatous inflammation with multinucleate giant cell formation and abundant intracellular acid-fast bacilli, consistent with a mycobacterial aetiology. PCR testing of the fresh tissue from the satellite lesion and subsequent sequence analysis identified Mycobacterium sp. strain Tarwin. The skin lesion was surgically excised and clarithromycin 62.5 mg twice daily was administered to the cat for 25 days. CONCLUSION: There was no recurrence of the lesion at the time of writing, 16 months after the surgery. This is the second autochthonous case of feline leprosy caused by M. sp. strain Tarwin originating in New South Wales, Australia.

Detection and identification of mycobacteria in fixed stained smears and formalin-fixed paraffin-embedded tissues using PCR.

OBJECTIVE: To determine the feasibility of using polymerase chain reaction to amplify DNA from methanol-fixed, Romanowsky-stained and Ziehl-Neelsen-stained smears to confirm the presence of mycobacteria. MATERIALS AND METHODS: Tissue was obtained from 10 archival slides and 27 slides from a prospective series of consecutive cases. Phosphate buffered saline (500 µL) was pipetted onto a stained smear (on a glass slide) using a disposable filtered pipette tip. The material adherent to the slide was scraped from its surface and drawn up into the saline. Routine DNA extraction and purification was carried out before nested polymerase chain reaction testing targeting the 16S-23S internal transcribed spacer region or a TaqMan real-time polymerase chain reaction. The real-time polymerase chain reaction was also used on thick sections cut from formalin-fixed paraffin-embedded tissue blocks from 24 canine leproid granulomas. RESULTS: Mycobacterial DNA was detected in 34 of 37 slides. Polymerase chain reaction products could not be amplified from three archived smears stained using the Ziehl-Neelsen acid-fast method, probably because its harsher fixation damaged the DNA. With the nested polymerase chain reaction, species identification using internal transcribed spacer sequence analysis was achieved in all instances, diagnosing a wide range of mycobacteria. The real-time polymerase chain reaction detected Mycobacterium sp. CLG DNA within all 24 formalin-fixed paraffin-embedded specimens tested. CLINICAL SIGNIFICANCE: This technique should provide a non-invasive and cost-effective means of diagnosing mycobacterial infections.

Inguinal panniculitis in a young Tasmanian devil (Sarcophilus harrisii) caused by Mycobacterium mageritense.

A 1-year-old, entire male Tasmanian devil living in captivity was presented because of a nodular inguinal lesion that subsequently developed a draining sinus tract. A second, similar lesion developed later in the ipsilateral axillary region. A deep representative biopsy specimen of abnormal subcutaneous tissue showed chronic active pyogranulomatous inflammation and beaded Gram-positive and acid-fast bacilli situated in lipid vacuoles within the lesion. A rapidly growing Mycobacterium species, shown subsequently to be M. mageritense, was grown from a swab of the primary lesion. It was susceptible to tetracyclines (including doxycycline) and moxifloxacin in vitro. The lesions resolved following treatment with doxycycline monohydrate (50 mg PO once daily) and then moxifloxacin (10 mg/kg PO for 20 days). The infection probably resulted from inoculation of subcutaneous tissues by material containing this Mycobacterium following fight or bite injuries. The presentation is reminiscent of similar lesions attributable to rapidly growing mycobacterial infections of the subcutis observed in domestic cats and quolls.

Phaeochromocytoma in two coatimundi (Nasua nasua).

Two unrelated coatimundi (Nasua nasua) had bilaterally enlarged adrenal glands at necropsy, and sections of the glands from both animals had histopathological features consistent with neoplasia. They were differentiated from an adrenal cortical tumour on the basis of their light microscopical morphology, immunoperoxidase staining and electron microscopic studies and a final diagnosis of phaeochromocytoma was made. To the authors' knowledge, these are the first reported cases of phaeochromocytoma in coatimundi.

Papillary ductal adenocarcinoma in the mammary glands of two horses.

Mammary gland neoplasms in horses are uncommon and may initially be confused with mastitis. Masses from the mammary glands of two horses with chronic discharges were examined by cytology and histopathology. Both masses were diagnosed as papillary ductal adenocarcinomas with extensive intraductal and intralobular involvement and only focal infiltration of the adjacent stroma. Complementary immunohistochemical studies were made of both fresh and formalin-fixed tumour tissue, and attempts were made to assess the steroid receptor status of fresh tissue biochemically to assess the possibility of hormonal treatment as an adjunct to surgery. The results of these tests for oestrogen and progesterone receptors were negative.

Malignant mast cell neoplasia with local metastasis in a horse.

A 12-year-old Arab stallion was presented with a chronically swollen right carpus resulting in profound lameness of the same leg. An incisional biopsy of subcutaneous tissue from the right carpus submitted for cytology and histopathology revealed large numbers of eosinophils interspersed by substantial numbers of variably sized and granulated mast cells. Fungal culture of a subcutaneous tissue sample taken from the right carpus was negative. Serial full blood counts revealed persistent mature eosinophilia, not accompanied by a mastocytaemia, neutrophilia without left shift and persistent hyperfibrinogenaemia. After humane destruction, dissection of the affected limb revealed a thick layer of connective tissue deposited around the right carpal joint. Within the connective tissue were embedded many small 0.25-1 cm diameter yellow gritty nodules, which consisted of dystrophic calcification and necrotic cell debris. The tendons enveloped by the connective tissue mass had limited function. The right axillary lymph node was moderately enlarged, yellow-brown and moist. Histopathological examination revealed a moderately well differentiated mast cell neoplasm with evidence of metastasis to the regional lymph node. In horses, malignant mast cell neoplasia is rare, while metastasis has only been reported in one other horse. Eosinophilia associated with equine mast cell neoplasia has not been reported previously but is recorded in mast cell neoplasia in the dog.

Multiple congenital cardiac anomalies and idiopathic thoracic aortitis in a horse.

An echocardiographical and clinical pathological investigation of the rapid loss of weight by a yearling thoroughbred filly revealed an atrial septal defect, a ventricular septal defect and hyperfibrinogenaemia. A post mortem examination confirmed the cardiac abnormalities and revealed a severe thoracic aortitis. It is proposed that the idiopathic thoracic aortitis contributed to the horse's compromised cardiovascular homoeostasis.

Bryophyllum pinnatum poisoning of cattle.

Two adult cattle died within 48 h of being fed a large amount of Bryophyllum pinnatum plants collected from a house garden. Clinical signs became apparent the day after feeding and included hypersalivation, ataxia, severe cardiac arrhythmia and laboured respiration. The main necropsy findings were acute rumenitis, reduction of bronchiolar lumens and emphysema.

Management of equine sarcoids: 1975-93.

Treatment options for equine sarcoids are briefly reviewed and the results of a retrospective study of 63 cases of equine sarcoid (66 lesions) treated by clinicians from the Rural Veterinary Centre, Camden, Australia from 1975 to 1993 presented. Five different treatments were employed in the management of these 66 lesions, including surgical excision alone or in combination with cryotherapy, radiotherapy, immunotherapy and tumour transfer to a subcutaneous site on the neck. The majority of cases were treated with surgical excision alone (18/66), excision followed by cryotherapy (31/66) and immunotherapy (16/66), with success rates of 28%, 42% and 81% respectively. Success was defined as no sign of recurrence of the lesion at the time of follow-up, at least 6 months later.