Focal mucinosis in dogs: seven cases and review of cutaneous mucinoses of man and animals

Case report: Sublingual mucinosis in a dog

A 11-month-old male intact Shar-Pei (26. 5 kg) was presented for a bilateral sublingual swelling of 4 months duration. The exploration of the oral cavity highlighted the presence of bilateral sublingual swellings, primarily consistent with bilateral ranula. The bilateral disease was treated with two subsequent surgeries 4 weeks apart. During the surgery, after removing an elliptical portion of the mucosa of the sublingual swelling, the presence of gelatinous tissue was visualized, and no saliva was present. The result of histological exam was oral mucinosis. At the subsequent follow-up the dog was in excellent conditions, without any symptoms. 1 month after the last operation, the dog underwent a visit in sedation to better evaluate the oral cavity. Both surgical sites were well-healed and without the presence of relapses. Upon 8 months follow-up the patient remained free of disease. This is the first reported case of oral mucinosis in sublingual mucosa in dogs. In this case the surgical treatment was curative.

Inheritance of Monogenic Hereditary Skin Disease and Related Canine Breeds

The plasticity of the genome is an evolutionary factor in all animal species, including canines, but it can also be the origin of diseases caused by hereditary genetic mutation. Genetic changes, or mutations, that give rise to a pathology in most cases result from recessive alleles that are normally found with minority allelic frequency. The use of genetic improvement increases the consanguinity within canine breeds and, on many occasions, also increases the frequency of these recessive alleles, increasing the prevalence of these pathologies. This prevalence has been known for a long time, but mutations differ according to the canine breed. These genetic diseases, including skin diseases, or genodermatosis, which is narrowly defined as monogenic hereditary dermatosis. In this review, we focus on genodermatosis sensu estricto, i.e., monogenic, and hereditary dermatosis, in addition to the clinical features, diagnosis, pathogeny, and treatment. Specifically, this review analyzes epidermolytic and non-epidermolytic ichthyosis, junctional epidermolysis bullosa, nasal parakeratosis, mucinosis, dermoid sinus, among others, in canine breeds, such as Golden Retriever, German Pointer, Australian Shepherd, American Bulldog, Great Dane, Jack Russell Terrier, Labrador Retriever, Shar-Pei, and Rhodesian Ridgeback.

Scleromyxoedema in a dog

BACKGROUND

In humans, scleromyxoedema is a chronic progressive skin condition traditionally characterized by deposits of mucin, increased number of fibroblasts and fibrosis in the skin, and by systemic disease. Thyroid disease is typically absent. A monoclonal gammopathy is usually present, as are other comorbidities. Descriptions of scleromyxoedema in the veterinary literature are limited to a single feline case. One dog, previously reported as having papular mucinosis, exhibited features that matched the more current diagnostic criteria of scleromyxoedema.

OBJECTIVES

To describe generalized papular mucinosis in a dog with systemic illness and to compare the signs with those of human lichen myxoedematosus conditions, specifically scleromyxoedema.

RESULTS

A nine-year-old female, spayed English springer spaniel dog presented with generalized papules and nodules (0.5-5 cm) on the body and proximal fore and hind limbs, sparing the face and distal limbs distal to carpi/tarsi. Larger nodules were erythematous. Nodules occurred in proximal limb muscles. The dog had concurrent osteoarthritis of the elbows and coxofemoral joints, developed generalized weakness, declined in health and was euthanized. Thyroid disease was lacking and a monoclonal gammopathy was not present. Histopathological evaluation revealed the classic triad of mucin, fibroblast proliferation and fibrosis with very mild inflammation, as described for humans.

CONCLUSION AND CLINICAL IMPORTANCE

We document scleromyxoedema in a dog with significant morbidity and features of the human disease. Recognizing the typical histopathology is important for identifying cases and to establish a diagnosis. Systemic evaluation is important to identify evidence of internal disease and associated comorbidities, which are common, variable, and impact classification and prognosis in humans.

Cutaneous mucinosis in a strain of brown-egg laying chickens

Cutaneous mucinosis is a cutaneous disorder described in humans, dogs, and rarely cats but never reported in birds. Twenty-six brown egg-laying chickens between ages 43 and 46 weeks had a history of feather loss, scaly, dry skin, weight loss, and decreased egg production. Microscopic findings in the skin included fragmentation of collagen bundles and interstitial, periadnexal, and perivascular dermal accumulation of wispy, mildly basophilic material that was also occasionally observed within the follicular epithelium. A moderate lymphoplasmacytic and heterophilic perivascular dermatitis was also observed. The wispy to granular material was diffusely Alcian blue positive and periodic acid-Schiff negative (consistent with mucin), suggesting a diagnosis of primary or secondary cutaneous mucinosis. The cause of this condition could not be determined.

Oral Focal Mucinosis of the Tongue: A Rare Clinical Case

Oral focal mucinosis (OFM) is a rare mucosal lesion of unknown etiopathogenesis. It is considered the oral counterpart of cutaneous focal mucinosis. From the anatomo-pathological point of view it is characterised by a focal degeneration of myxoid type of connective tissue. A literature survey revealed 50 reports of OFM cases worldwide. Here, we present an even more rare case with tongue involvement. Particular emphasis is placed on diagnostic-differential aspects of this kind of lesion, both from the clinical and the histopathological point of view, in respect to other manifestations of tongue mucosa.

Scleromyxedema-like Syndrome With Systemic Involvement in a Cat

Scleromyxedema—the generalized form of lichen myxedematosus, a primary mucinosis—is a rare disease in human patients. It is characterized by dermal mucin deposits, increased numbers of fibroblasts, and variable fibrosis in the absence of thyroid disease. It is accompanied in 80% of cases by a monoclonal gammopathy. To date, scleromyxedema with systemic involvement has not been documented in domestic animals. This is the first report of a scleromyxedema-like syndrome in a cat, which had a substantial deposition of mucin in the dermis of the head and paws with a mild gammaglobulinemia of 2.25 g/dl (reference range, 1.39–2.22 g/dl). At necropsy, multiple nodules of connective tissue intermingled with mucin deposits were conspicuous on the surface of thoracic and abdominal organs. Such severe systemic accumulations of mucin have not been reported in human or veterinary medicine.

Development and characterization of a canine oral mucosa equivalent in a serum-free environment

The objectives of this study were to develop a serum-free system for culturing canine oral keratinocytes, the construction and characterization of a canine ex vivo produced oral mucosa equivalent (EVPOME), and transduction green fluorescent protein (GFP) into keratinocytes as a post-grafting tracking marker. Dissociated canine buccal mucosa keratinocytes were cultured in a chemically defined serum-free medium, Epilife trade mark. First-passage keratinocytes were transfected with the GFP gene using a lentiviral vector, sorted by flow cytometer and seeded onto a dermal equivalent, AlloDerm(R) to form EVPOMEs. The EVPOME was characterized by histology and immunohistochemistry, for p63, Ki-67, and involucrin. Laser confocal microscopy was used to locate GFP-transfected keratinocytes within the EVPOME. Cultured canine oral keratinocytes grew rapidly over the first three passages and then the proliferative rate decreased. The canine EVPOME formed a well-stratified epithelial layer. The majority of p63 and Ki-67 immunopositive cells were located in the basal layer whereas cytoplasmic involucrin expression was seen in the suprabasal layers, similar to native canine buccal mucosa. Under laser confocal microscopy, significant green fluorescence was observed throughout the EVPOME. In conclusion, canine EVPOMEs were successfully fabricated in a defined serum-free system with similar characteristics to native buccal mucosa. GFP-transfected canine oral keratinocytes could be identified within the EVPOME.

Oral focal mucinosis: report of 15 cases and review of the literature

AIMS

To describe 15 cases of oral focal mucinosis (OFM) and compare these to previously reported cases.

METHODS

Cases diagnosed as OFM in the period 1981-2003-were reviewed. Clinical information provided at the time of submission of each specimen was retrieved and supplemented by additional clinical details provided by the respective clinician at the time of compilation of this paper. The literature was reviewed.

RESULTS

OFM presented as an innocuous soft tissue swelling that may be either pedunculated or sessile. The gingiva was confirmed as the most common site for OFM, with a predominance of females affected. Microscopically, OFM is characterised by an area of myxoid tissue which is usually well-defined. The lesion is periodic acid-Schiff (PAS)-negative and alcian blue-positive, with pre-digestion with hyaluronidase preventing the alcian blue staining. As the differential diagnosis includes myxoid neural lesions, S100 staining is important in establishing the diagnosis, with cases of OFM being negative.

CONCLUSIONS

The cause of OFM remains unknown. The cases presented in this paper bring OFM to the attention of anatomical pathologists when considering the differential diagnosis of myxoid lesions of the oral cavity.

Histochemical study of cutaneous mucins in hypothyroid dogs

A dermal mucinosis, visualized as dermal alcianophilic material, is occasionally present in canine hypothyroidism (myxedema). Various histochemical reactions (alcian blue/periodic acid-Schiff [PAS], alcian blue at pH 2.6, alcian blue at pH 1.0, critical electrolytical concentrations with and without dimethylsulfoxide, differential hydrolysis by hyaluronidases) were performed on skin biopsies from six dogs (four females and two males ranging from 8 to 13 years) affected by hypothyroidism, all of them presenting dermal mucinosis in hematoxylin and eosin-stained sections. In these dogs, the only polysaccharidic compound involved in the dermal mucinosis was hyaluronic acid. In this study, hyaluronic acid dermal deposits of hypothyroid dogs were significantly different from those of controls in subepidermal connective tissue and loose reticular connective tissue but not in periadnexal zones. We recommend the combined alcian blue/PAS reaction as a routine technique to assess dermal mucinosis in hypothyroid dogs.

Skin diseases of the Chinese Shar-Pei

This article deals with the unique skin disorders seen only in the Shar-Pei. The difference between skin diseases in Shar-Pei and other breeds is described. Prevention and treatment are discussed. Suggestions are given to alter the breed's anatomy slightly to decrease the genetic predisposition to certain dermatoses.

Focal mucinosis of the upper aerodigestive tract in children

Cutaneous mucinosis is an uncommon lesion characterized by mucin accumulation in the dermis. Rarely, mucinosis may arise in the oral cavity; reported cases have been observed in patients older than 16 years. We identified two children younger than 5 years of age with focal mucinosis of the upper aerodigestive tract. A 3-year-old boy had been intubated at age 2 months, suffered from recurrent respiratory infections, and developed mucinosis of the larynx, a previously unreported site for this unusual lesion. The second patient, a 4-year-old girl with a cleft palate, developed palatine mucinosis.