Subcutaneous panniculitis-like T-cell lymphoma: Morphological, immunophenotypical and clonality assessment in six cats.

BACKGROUND: Primary cutaneous lymphoma represents 0.2%-3% of all feline lymphomas, with nonepitheliotropic lymphomas being the most common. In humans and dogs, subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a primary nonepitheliotropic lymphoma with a T-cell phenotype developing in the subcutis and often mimicking inflammation. OBJECTIVE: The aim of this report is to describe pathological, phenotypical and clonal features of SPTCL in cats. ANIMALS: Six cats with SPTCL were included in this study. MATERIALS AND METHODS: Skin biopsies were formalin-fixed, routinely processed and stained. Histological and immunohistochemical investigation for anti-CD18, CD204, CD79a, CD20, CD3, FeLVp27and FeLVgp70 and clonality assessment were performed. RESULTS: Four male and two female domestic shorthair cats, mean age 11.2 years, developed SPTCL in the abdominal (three), inguinal (two) and thoracic (one) regions. Variably pleomorphic neoplastic lymphoid cells were present in the panniculus in percentages, expanding the septa (six of six) and extending into fat lobules in one of six cats. Tumours were associated with elevated numbers of neutrophils (five of six), lesser macrophages (six of six) and variable necrosis (six of six). Neoplastic cells expressed CD3+ (six of six), with clonal T-cell receptor rearrangement detected in five of six cats. CONCLUSIONS AND CLINICAL RELEVANCE: This is the first description of SPTCL in cats. Lesions can be confused with panniculitis, leading to delay in diagnosis and therapy. Awareness of this neoplastic disease is relevant to avoid misdiagnoses and to gain greater knowledge about the disease in cats.

Immune-mediated pyogranulomatous panniculitis with hypercalcemia in a dog.

An 11-year-old neutered male large crossbreed dog was presented for investigation because of a 10-day history of progressive lethargy, hyporexia, and pyrexia. Physical and dermatological examinations were unremarkable. Blood biochemical analysis identified a marked total and ionized hypercalcemia and increased C-reactive protein concentration. Bicavitary computed tomography screening for causes of the dog's clinical and biochemical abnormalities identified a diffuse panniculitis. Histopathological examination of full-thickness skin biopsies was consistent with pyogranulomatous inflammation. Extensive histochemical staining revealed no infectious etiology. Complete clinical and biochemical remissions were observed after starting immunosuppressive, followed by tapering, doses of prednisolone, supporting an immune-mediated etiology. Key clinical message: Sterile, immune-mediated pyogranulomatous inflammation should remain a differential diagnosis for hypercalcemia in dogs. Significant dermatological disease may occur without visible abnormalities.

Panniculite pyogranulomateuse à médiation immunitaire avec hypercalcémie chez un chienUn grand chien croisé mâle castré de 11 ans a été présenté pour examen en raison d'antécédents de léthargie progressive, d'hyporexie et de pyrexie depuis 10 jours. Les examens physiques et dermatologiques étaient sans particularité. L'analyse biochimique du sang présentait une hypercalcémie totale et ionisée marquée et une concentration accrue de protéine C-réactive. Le dépistage par tomodensitométrie bicavitaire des causes des anomalies cliniques et biochimiques du chien a identifié une panniculite diffuse. L'examen histopathologique des biopsies cutanées de pleine épaisseur était compatible avec une inflammation pyogranulomateuse. Un examen par coloration histochimique extensive n'a révélé aucune étiologie infectieuse. Les rémissions cliniques et biochimiques complètes ont été observées après le début du traitement immunosuppresseur, suivies d'une diminution progressive des doses de prednisolone, confirmant une étiologie à médiation immunitaire.Message clinique clé:L'inflammation pyogranulomateuse stérile à médiation immunitaire doit rester un diagnostic différentiel de l'hypercalcémie chez le chien. Une maladie dermatologique importante peut survenir sans anomalies visibles.(Traduit par Dr Serge Messier).

Common superficial and deep cutaneous bacterial infections in domestic animals: A review.

The skin covers the external surface of animals, and it is constantly exposed to and inhabited by different microorganisms, including bacteria. Alterations in the skin barrier allow commensal and/or pathogenic bacteria to proliferate and penetrate deep into the lower layers of the skin. Being the first barrier to the external environment, the skin is prone to injuries, allowing the penetration of microorganisms that may lead to severe deep infections. Companion animals, especially dogs, are prone to bacterial infections, often secondary to allergic dermatitis. When environmental conditions are unfavorable, horses, cattle, sheep, and goats can develop superficial infections, such as those caused by Dermatophilus congolensis. Deep inflammation is commonly caused by Mycobacterium spp., which results in granulomatous to pyogranulomatous dermatitis and panniculitis. Likewise, bacteria such as Nocardia spp. and Actinomyces spp. can cause deep pyogranulomatous inflammation. Bacteria that lead to deep necrotizing lesions (eg, necrotizing fasciitis/flesh-eating bacteria) can be severe and even result in death. This review includes an overview of the most common cutaneous bacterial infections of domestic animals, highlighting the main features and histologic morphology of the bacteria, cutaneous structures involved, and the type of inflammatory infiltrates.

Palisading granulomatous dermatitis and panniculitis (palisading granuloma) of dogs.

Palisading granulomatous dermatitis and panniculitis is recognized in various cutaneous inflammatory lesions secondary to presumed collagen damage. Cutaneous nodules with a palisading arrangement of histiocytes surrounding foci of collagen degeneration have been clinically termed palisading granuloma in dogs. Study aims were to characterize the cellular infiltrate of canine palisading granuloma and document salient clinical features. Inclusion criteria were met for 36 dogs and encompassed nodular dermal and subcutaneous histiocyte-predominant cellular infiltrates targeting and enveloping collagen fibers/necrotic foci with palisading configurations. Infectious causes were ruled out via standard histochemical stains and/or clinical data. Medical records were reviewed for signalment, clinical features, treatment, outcome, and comorbidities. Immunohistochemistry (IBA1, CD204, E-cadherin) and Masson's trichrome stain were used to assess histiocytic populations and dermal collagen, respectively. The histiocytes had moderate or strong immunolabeling for IBA1 and CD204 in 36/36 dogs (100%) and mild positive immunolabeling for E-cadherin in 3/36 dogs (8%). Alteration of collagen was graded as moderate or strong in 32/36 dogs (89%) and mild in 3/36 dogs (8%). Large breeds predominated with 30/36 dogs (83%) being ≥23 kg. Focal nodules were identified in 31/36 dogs (86%). The head/face were involved in 19/36 dogs (53%) and the extremities in 18/36 dogs (50%). Lesions from the 5/36 dogs (14%) with multiple nodules contained prominent eosinophilic infiltrates. Following excision, there was no evidence of recurrence. In conclusion, palisading granulomas are a distinct, non-neoplastic, histiocyte-predominant inflammatory condition in dogs associated with altered dermal collagen and favorable prognosis.

Pyogranulomatous panniculitis in a domestic cat associated with Pseudomonas luteola infection.

Pseudomonas luteola, a pathogen causing disease in humans, has in animals been reported only in rainbow trout and ferrets. This case report describes pyogranulomatous panniculitis in a cat associated with P. luteola infection. Organisms were seen histologically and identified with PCR and sequencing. Lesions resolved after treatment with marbofloxacin.

Pseudomonas luteola, un pathogène de l'homme, a été décrit chez l'animal seulement chez le furet et la truite arc en ciel. Ce cas clinique décrit une panniculite pyogranulomateuse chez un chat associée à une infection à P. luteola. Les organismes ont été vus à l'examen histopathologique et identifiés par PCR et séquençage. Les lésions se sont résolues après un traitement à la marbofloxacine.

Pseudomonas luteola, un patógeno que causa una enfermedad en los seres humanos, se ha reportado en animales solo en truchas arco iris y hurones. Este caso clínico describe una paniculitis piogranulomatosa en un gato asociada con una infección por P. luteola. Los organismos se observaron histológicamente y se identificaron mediante PCR y secuenciación. Las lesiones se resolvieron después del tratamiento con marbofloxacina.

Pseudomonas luteola é um patógeno causador de doença em humanos e, em animais, há relatos de sua ocorrência apenas em furões e trutas arco-íris. Este relato descreve um caso de paniculite piogranulomatosa em um gato associada à infecção por P. luteola. Os microrganismos foram observados histologicamente e identificados por PCR e sequenciamento. As lesões foram resolvidas após tratamento com marbofloxacino.

Mycobacterium porcinum causing panniculitis in the cat.

A 4-year-old domestic shorthair cat was presented with a 7-month history of nodules and draining fistulous tracts of the ventral abdomen. Histopathological examination of affected tissue revealed acid-fast bacilli stained by the Ziehl-Neelsen procedure. Deep tissue culture confirmed infection with a rapidly growing mycobacterium, and gene sequencing characterized the organism as Mycobacterium porcinum. Treatment with pradofloxacin and doxycycline resulted in clinical resolution of the lesions. On continued antibiotic therapy 7 months later, there was no local recurrence nor were there clinical signs associated with distant spread of the infection. This is the first clinical description of a feline infection with this organism. Key clinical message: This is the first clinical description of mycobacterial panniculitis in a cat due to genetically characterized Mycobacterium porcinum. This case report highlights a disease entity that can present a diagnostic and therapeutic challenge to clinicians.

Panniculite chez un chat causée par Mycobacterium porcinum . Un chat domestique à poil court âgé de 4 ans fut présenté avec une histoire d'une durée de 7 mois de nodules et de trajets fistulaires drainants à l'abdomen ventral. Un examen histopathologique des tissus affectés a révélé la présence de bacilles alcoolo-acidorésistants par coloration de Ziehl-Neelsen. Une culture des tissus profonds confirma l'infection par des mycobactéries à croissance rapide, et le séquençage génétique caractérisa l'organisme comme étant Mycobacterium porcinum. Un traitement avec de la pradofloxacine et de la doxycycline permit une résolution clinique des lésions. Sept mois plus tard, à la suite d'une antibiothérapie continue, il n'y avait aucune récurrence locale ni de signe clinique associé avec une dissémination de l'infection. Ceci est la première description clinique d'une infection féline associée à ce microorganisme.Message clinique important :Ceci est la première description clinique d'une panniculite à mycobactérie chez un chat associée à Mycobacterium porcinum caractérisé génétiquement. Ce rapport de cas met en évidence une maladie qui peut représenter un défi diagnostique et de traitement pour les cliniciens.(Traduit par Dr Serge Messier).

Subcutaneous Panniculitis-Like T-cell Lymphoma in Dogs: Morphologic and Immunohistochemical Classification.

Canine nonepitheliotropic cutaneous T-cell lymphomas (NECTCL) are poorly characterized. In humans, a number of distinct subtypes of NECTCL have been recognized, including subcutaneous panniculitis-like T-cell lymphoma (SPTCL). Five dogs with subcutaneous T-cell lymphomas histologically similar to SPTCL in humans are herein described. The mean age was 8.5 years (5.5 to 12 years). No breed or sex predilection was identified in this small cohort. Two dogs presented with an acute onset of multiple skin masses and 3 dogs had solitary masses with subsequent development of multiple smaller masses within 0.5 to 2 months post-diagnosis without treatment. Locations, when specified, included shoulder, neck, and ventral abdomen. Two dogs were euthanized following diagnosis and one dog treated with chemotherapy (CCNU) survived 7 months post-diagnosis. Histologically, all cases were characterized by proliferations of either small to intermediate or large sized, CD3-positive T cells that infiltrated the subcutis in a lace-like pattern and frequently rimmed adipocytes. No epitheliotropism was observed, neoplastic cells were often karyorrhectic, and there were regions of extensive necrosis. Heavy infiltrates of histiocytes with prominent phagocytosis masked the lymphoid neoplastic cell population in some sections. A clonal T-cell receptor gamma gene rearrangement was found in 4 of the 5 cases. While SPTCLs typically have a less aggressive clinical course in humans, their biological behavior in dogs remains to be determined. In summary, SPTCL may represent a distinct entity in dogs and needs to be accurately diagnosed to better determine clinical behavior.

Analysis of Bacterial and Fungal Nucleic Acid in Canine Sterile Granulomatous and Pyogranulomatous Dermatitis and Panniculitis.

Next generation sequencing (NGS) studies are revealing a diverse microbiota on the skin of dogs. The skin microbiota of canine sterile granulomatous and pyogranulomatous dermatitis (SGPD) has yet to be investigated using NGS techniques. NGS targeting the 16S rRNA and ITS-1 region of bacterial and fungal DNA, respectively, were used to investigate if bacterial and fungal DNA were associated with skin lesions in cases of canine SGPD. The study included 20 formalin-fixed paraffin-embedded (FFPE) skin samples and 12 fresh samples from SGPD-affected dogs, and 10 FFPE and 10 fresh samples from healthy dogs. DNA was extracted from deep dermis and panniculus, and microbial DNA was amplified using primers targeting the bacterial 16S rRNA V1-V3 and fungal ITS-1 regions. The amplified DNA was utilized for NGS on an Illumina MiSeq instrument. The sequences were processed using QIIME. No differences in fungal or bacterial alpha diversity were observed between the SGPD and control samples. Beta diversity analysis demonstrated differences in the bacterial communities between SGPD and control, but not in the fungal communities. Compared to controls, the family Erysipelotrichaceae and genus Staphylococcus were significantly more abundant in the SGPD FFPE samples, and genus Corynebacterium were more abundant in fresh samples. The bacteria found to be more abundant in SGPD are common inhabitants of skin surfaces, and likely secondary contaminants in SGPD cases. This study provides additional evidence that SGPD lesions are likely sterile.

Canine sterile nodular panniculitis: a retrospective study of 39 dogs.

BACKGROUND: Canine sterile nodular panniculitis (SNP) is an inflammatory disease of the panniculus that is typically managed with immunomodulatory or immunosuppressive treatments. It has been reported to be a cutaneous marker of an underlying systemic disease. HYPOTHESIS/OBJECTIVES: To assess the presence or absence of concurrent systemic diseases associated with canine SNP and to document breed predispositions. ANIMALS: Thirty nine dogs presented to a veterinary teaching hospital from 1990 to 2012 which met inclusion criteria. METHODS: Inclusion in this retrospective study required a diagnosis of SNP via histopathological analysis and negative special stains for infectious organisms. Breed distributions of affected dogs were compared to all other dogs examined at this hospital during the study period. Correlations between the histological pattern of panniculitis and the histological presence of dermatitis, clinical presentation of lesions, dog breed and therapeutic outcomes were assessed. RESULTS: Australian shepherd dogs, Brittany spaniels, Dalmatians, Pomeranians and Chihuahuas were significantly over-represented, but correlations between inflammatory patterns of panniculitis and other histological and clinical factors were not identified. Based on the information available in medical records, 32 dogs (82.1%) had no concurrent systemic diseases identified. Four dogs had concurrent polyarthritis, which may be related to SNP through unknown mechanisms. CONCLUSIONS/CLINICAL IMPORTANCE: This study identified several novel breed predilections for SNP; it failed to find any clear correlations with associated systemic diseases other than polyarthritis. The histological inflammatory pattern of SNP does not predict therapeutic outcome.

Nodular pyogranulomatous panniculitis due to Leishmania infantum infection in a domestic ferret (Mustela putorius furo).

Leishmaniosis is a vector-borne disease caused by different Leishmania species and transmitted by phlebotomine sand flies under natural conditions in Europe. Scientific information related to Leishmania infantum in dogs is extensive, where less information is available in cats and other companion animals. Recently, first clinical cases of L.infantum infection in domestic ferrrets (Mustela putorius furo) have been described. However, clinical information on leishmaniosis in this species is limited A 15-month-old male neutered domestic ferret was presented with chronic weight loss and the presence of coalescent, erythematous and firm subcutaneous nodules in the ventral abdominal subcutis. A fine-needle aspiration of these nodules was performed and the cytological examination revealed a granulomatous inflammation with the presence of macrophages contained a number of oval organisms with an eccentric nucleus and pale cytoplasm, compatible with Leishmania spp. amastigotes compatible with Leishmania spp. amastigotes. The nodules were surgically excised and histological examination showed a severe multifocal pyogranulomatous panniculitis. Specific immunohistochemistry and qPCR for L. infantum from excised nodules were positive. Additionally, L. infantum was cultured and isolated from the nodules by a fine-needle aspiration. An in-house Western Blot test for L. infantum was performed in serum sample and a positive result was obtained. This is the first reported case of nodular pyogranulomatous panniculitis due to L. infantum infection in a domestic ferret. Further studies are necessary to determine the relevance of domestic ferrets in the transmission of leishmaniosis. The description of new clinical forms of the disease is important as it can assist veterinarians in identifying these new clinical presentations.

Resolution of feline Mycobacterium panniculitis despite protracted treatment with methylprednisolone acetate.

Saprophytic or non-tuberculous mycobacteria are ubiquitous in the environment. They can cause opportunistic infections when the skin is broken and typically manifest with draining sinus tracts or cutaneous nodules. This report details the first confirmed Mycobacterium smegmatis panniculitis in a cat in South Africa. Despite repeated treatment with methylprednisolone acetate for six months prior to diagnosis, the cat made an uneventful recovery once switched to doxycycline and marbofloxacin.

Sterile panniculitis in dogs: new diagnostic findings and alternative treatments.

The objective of this study was to analyse the underlying diseases, diagnostic findings and treatment outcomes in 10 dogs with sterile panniculitis. There was no significant breed association in this study (P = 0.86).The median age of the dogs was 7.4 years. Concurrent diseases included atopic dermatitis (four dogs), acute pancreatitis (two dogs) and primary hypoadrenocorticism (one dog), with no concurrent conditions detected in three dogs. There was no significant association with the sterile panniculitis (P = 0.57). Well-circumscribed firm nodules were noted in seven dogs, and ill-defined soft nodules were observed in three dogs. Bacterial and fungal cultures of biopsy samples were negative in all cases. Fine-needle aspiration cytology of the nodules revealed pleomorphic mesenchymal cells in all of the well-circumscribed firm nodules, whereas numerous inflammatory cells and adipose cells were evident in soft nodules. These results indicate that firm nodules in panniculitis could be misdiagnosed as tumours. Immunosuppressive therapy was used in eight cases. Topical dexamethasone was used in four dogs, intralesional dexamethasone in one dog, oral prednisolone plus ciclosporin in two dogs and oral prednisolone only in one dog. The remaining treatments were surgical excision and systemic cefalexin in one dog each. The lesions regressed within 1 week in all cases, with more rapid remission following systemic immunosuppressive therapy. This study suggests that cytology may be misinterpreted as neoplastic, especially with firm lesions. In addition, topical glucocorticoid therapy should be further evaluated as a potential treatment for canine sterile panniculitis.

Mycobacterium setense isolated from a cat with atypical mycobacterial panniculitis.

Atypical mycobacterial panniculitis was diagnosed in a cat. Mycobacterium setense was identified as causative agent by 16 S rRNA gene sequence analysis. This a gram-positive rod-shaped acid-fast bacterium belonging to Mycobacterium fortuitum group was never reported before in diseased animals. Resistance to doxycycline and clarithromycin was detected. During treatment with pradofloxacin, additional resistance to fluoroquinolones developed which was due to a mutation in the gyrase gene gyrA (S90W exchange). Despite of antimicrobial treatment for 33 months the patient did not fully recover. Species identification and susceptibility testing for choosing adequate antimicrobial treatment is recommended in cases of feline mycobacterial panniculitis.

Canine sterile nodular panniculitis: a retrospective study of 14 cases.

BACKGROUND: Sterile nodular panniculitis (SNP) is an uncommon inflammatory condition of subcutaneous fat that can be idiopathic, but has also been associated with underlying conditions such as pancreatic disease or systemic lupus erythematosus (SLE). The pathogenesis and clinical course of the condition are not well understood. OBJECTIVES: To retrospectively review cases of SNP associated with systemic signs, concurrent disease, or both and characterize the clinical, laboratory, imaging, and histopathologic findings, treatment, and response to treatment. ANIMALS: Fourteen dogs with histologically confirmed SNP diagnosed between 1996 and 2008. METHODS: Retrospective study. RESULTS: Skin lesions were ulcerated or draining nodules in 9 dogs and nonulcerative subcutaneous nodules in 5. Most dogs had systemic signs, such as fever, inappetence, lethargy, and multiple lesions. Common clinicopathologic findings included neutrophilia with or without left shift, increased alkaline phosphatase activity, mild hypoglycemia, hypoalbuminemia, and proteinuria. Concurrent diseases included pancreatic disease, SLE, rheumatoid arthritis, polyarthritis, lymphoplasmacytic colitis, and hepatic disease. Dogs responded to immunosuppressive doses of corticosteroids when administered. Prognosis for recovery was related to the underlying disease process. CONCLUSIONS AND CLINICAL IMPORTANCE: SNP is not a single disease. Rather, it is a cutaneous marker of systemic disease in many cases. After thorough evaluation for concurrent disease and infectious causes, immunosuppressive treatment is often effective.

Panniculitis attributable to Mycobacterium goodii in an immunocompetent dog in Georgia.

CASE DESCRIPTION: A 5-year-old 38.3-kg (84.5-lb) mixed-breed dog was examined because of acute onset of lethargy and anorexia. Four days later, a raised, firm, warm 15 × 10-cm lesion was detected in the right caudal paralumbar area. CLINICAL FINDINGS: Cephalexin treatment yielded a poor response. Formalin-fixed tissue and fluid samples from the cystic areas of the lesion were submitted for cytologic and histologic examinations, routine bacterial and mycobacterial culture, and genus identification and 16S partial sequencing via PCR assays. Cytologic examination revealed chronic pyogranulomatous inflammation. Histologic examination by use of routine, Giemsa, silver, acid-fast, and modified acid-fast stains revealed multifocal nodular granulomatous panniculitis without identifiable organisms. Mycobacteria were initially identified via PCR assay and mycobacterial culture within 3 days. Mycobaterium goodii was speciated by use of partial 16S RNA sequence analysis. TREATMENT AND OUTCOME: The lesion resolved after long-term treatment with a combination of rifampin and clarithromycin and insertion of a Penrose drain. There has been no recurrence of the condition. CLINICAL RELEVANCE: M goodii is an environmental rapidly growing mycobacterium and is a zoonotic pathogen. Infections have not been previously reported in domestic animals in North America, although there are rare reports of infection in humans associated with surgery, especially surgical implants. Domestic animals are a potential sentinel for this non-tuberculous mycobacterial infection in humans, although lack of speciation in infections of domestic animals likely underestimates the potential public health importance of this pathogenic organism. Current microbiological molecular methods allow for a rapid and inexpensive diagnosis.

Alopecia in a black Labrador retriever associated with focal sub-follicular panniculitis and sebaceous adenitis.

A 6-year-old entire male black Labrador retriever was presented with nonpruritic multicentric, well-demarcated alopecia of 12-weeks duration. Skin biopsies from the margins of alopecic regions showed sebaceous adenitis and sub-follicular panniculitis. Biopsies from alopecic areas showed severe follicular atrophy with residual fibrous tracts, loss of sebaceous glands and lymphohistiocytic panniculitis beneath individual atrophic hair follicle groups. These features differed from previous reports of pilosebaceous diseases of dogs and appeared to extend the spectrum of inflammatory patterns in presumed immune-mediated adnexal diseases of this species. During the 12-month follow-up, there was partial hair regrowth without treatment but alopecia was permanent in the centre of larger lesions.

Nodular panniculitis in a cat with high alpha tocopherol concentration in serum.

A 5-year-old male neutered domestic shorthair cat suffered from recurrent solitary nodules in different subcutaneous body regions. Nodules were surgically removed and each time histopathological diagnosis was fat necrosis and fibrosing to pyogranulomatous panniculitis. After the second surgery the alpha (α)-tocopherol concentration in serum of the cat was examined and the result (21 mg/L) exceeded the upper limit of the reference interval (3-11 mg/L). Vitamin E amount in diet fed solely in the past was checked as studies have shown that vitamin E amounts in food significantly influence vitamin E concentrations in serum. For comparative purposes, α-tocopherol concentrations were determined in sera of healthy control cats. Additionally, vitamin E amount in wet food from different manufacturers was analysed using gas chromatography coupled to mass spectrometry (GC-MS). The results showed that the diet did not have higher vitamin E amounts compared to other diets. All control cats had similar high serum α-tocopherol concentrations. We conclude that panniculitis can occur despite high serum α-tocopherol concentrations in cats. Further studies are needed to redefine reference values of α-tocopherol in serum of cats.

Sterile traumatic panniculitis in a captive Brent goose.

A captive, adult female Brent goose (Branta bernicla) with a history of severe feather picking by its mate, was presented with 0.5-2.5 cm skin nodules on the head and neck. Histologic examination revealed a well-delineated dermal mass that surrounded an intact feather follicle and was composed of lakes of proteinaceous fluid and fibrin with scattered foamy macrophages and multinucleate giant cells. No bacteria or fungi were identified with histology, microbial culture, or PCR. Sterile panniculitis is an infrequent finding in animals and traumatic panniculitis is rarely sterile.

Sterile Pyogranulomatous Dermatitis and Panniculitis.

Canine sterile pyogranulomatous dermatitis and panniculitis is an infrequently described syndrome. No autoantigen, or exogenous antigen, inflammatory stimulus has been identified. This syndrome is characterized by pyogranulomatous nodules, plaques, and ulcers of variable extent and severity. Prodromal and concurrent nonspecific clinical and hematologic signs of inflammation may occur. This waxing and waning condition is typically responsive to systemic immunomodulation. Lifelong therapy may be required to prevent relapse. Differential diagnoses include bacterial and fungal nodular dermatoses, neoplasia, and cutaneous reactive histiocytosis. Diagnosis is achieved via diagnostic exclusion of infectious causes and supportive histopathology findings.

Epidural idiopathic sterile pyogranulomatous inflammation causing spinal cord compressive injury in five Miniature Dachshunds.

OBJECTIVE: To characterize the clinical signs, diagnostic and surgical findings, and outcome of dogs with idiopathic sterile pyogranulomatous inflammation (ISP) of epidural fat causing spinal cord compression. STUDY DESIGN: Retrospective study. ANIMALS: Dogs (n=5). METHODS: Dogs with epidural ISP (2002-2006) were identified retrospectively. Inclusion criteria were neurologic examination, myelography, and definitive diagnosis of ISP confirmed by surgery and histopathologic examination of epidural spinal cord compressive tissue. RESULTS: The most common clinical sign was paraparesis/paraplegia. No abnormalities were detected by laboratory testing or survey spine radiographs. On myelography, extradural spinal cord compressions were focal (dogs 1, 3, and 5) or multifocal (dogs 2 and 4). Surgical decompression of the spinal cord was completed by hemilaminectomy. Epidural fat collected surgically had pyogranulomatous inflammation of unknown cause and was histologically similar to subcutaneous ISP. All dogs had good long-term neurologic outcome (10-45 months follow-up). Some dogs had episodes of ISP at other sites before or after surgical treatment of epidural ISP, suggesting there may be a systemic form of ISP. CONCLUSION: Epidural ISP may cause a spinal cord compressive lesion in Miniature Dachshunds, which can be treated by surgical decompression of the spinal cord with or without administration of adjunctive steroids. CLINICAL RELEVANCE: Epidural ISP should be considered as a possible cause of thoracolumbar myelopathy for Miniature Dachshunds.