First Case of Degenerative Mucinotic Mural Folliculitis in Brazil

Reginaldo Pereira de Sousa Filho1*, Veronica Machado Rolim2, Keytyanne de Oliveira Sampaio3, David Driemeier2, Marina Gabriela Monteiro Carvalho Mori da Cunha3, Fernanda Vieira Amorim da Costa4 1Veterinary Faculty, Universidade Estadual do Ceará, CE, Brazil 2Department of Animal Pathology Universidade Federal do Rio Grande do Sul, RS, Brazil 3Department of Development and Regeneration-Katholiek Universitei Leuven, Leuven, Belgium 4Department of Animal Medicine, Universidade Federal do Rio Grande do Sul, RS, Brazil SOJ Veterinary Sciences Open Access Case Report


Introduction
Degenerative Mucinotic Mural Folliculitis is a rare disease that affects cats and is characterized by inflammation of the hair follicle, which leads to atrophy, degeneration and mucin production.It is an inflammatory reaction which takes place on the follicle wall, primarily affecting the external sheath of the hair above the follicular isthmus [1,2].In some cases it can also affect the infundibulum or the bulbar portion of the hair follicle [3].
The disease was first described in middle-aged or older animals, aged between four to ten years, with no breed predilection, although it seems that males are more often affected.First clinical manifestations are alopecia, especially in the face, head and neck, although it soon spreads to the limbs and the rest of the body.Usually there is an absence of itching or mild itching, but one case of severe pruritus has been reported [3].
(ALP), total T4 and glucose testing.All results were within the normal range for the species.It was also requested and enzyme immunoassay testing for the detection Of Feline Leukemia Virus Antigens (FeLV) and antibodies To Feline Immunodeficiency Virus (FIV).Results were positive for FIV.
On histopathologic evaluation, the epidermis showed regular hyperplasia, spongiosis and hydropic degeneration of the basal layer.It was also observed pigmentary incontinence and mixed perivascular inflammatory infiltrate in the superficial dermis and an intense mixed inflammatory infiltrate with a large number of lymphocytes, histiocytes, neutrophils and mast cells displaying a perifollicular pattern.Almost all hair follicles showed lymphocyte infiltration of the follicular epithelium of the isthmus indicating a mural folliculitis (Figure 2A).These lesions showed no signs of atypia.There was no evidence of follicular parasites.There was also a slight presence of mucin deposition displaying a perifollicular pattern and in the follicular epithelium evidenced by Alcian Blue stain (Figure 2B).
For Immunohistochemical Assay (IHC) for FIV and Feline Leukemia Virus (FeLV) it was used the method streptavidinbiotin linked to alkaline phosphatase.For both, antigen retrieval was performed using citrate buffer 96°C for 40 minutes.Sections were then incubated overnight at 4°C with the primary antibodies against FIV (Serotec) at 1:200 dilution and FeLV (Serotec) at 1:500 dilutions.Negative controls included buffer alone.Specific labeling was detected with biotinylated secondary antibodies bound to streptavidin-biotin (LSAB kit-AP, DakoCytomation).The color reaction was developed with Permanent Red chromogen (Dako) for 15 minutes.The follicular and superficial epithelium showed an intense nuclear expression of FIV (Figure 2C-F).In superficial dermis there was an intense nuclear and cytoplasmic expression of FIV in the inflammatory cells mixed perifollicular, perivascular and endothelial cells.It was not observed any immunostaining against FeLV.
Treatment consisted of methylprednisolone (20mg/ kg IM) every 15 days and Human Interferon α-2b (30 IU, VO), every 24 hours, for every other week.Approximately 40 days after, the animal showed clinical improvement, with a reduction of hyperkeratotic lesions.Nevertheless, there was significant weight reduction (500 g), although the patient maintained his appetite.The cat was then submitted to radiography of the chest which showed no evidence of intra-thoracic neoplasm.
After 60 days of treatment, the cat returned to the clinic in a worse state, presenting evident cachexia and a fistulated abscess in the region of the left mandible.Antibiotic therapy was prescribed with the use of cefovecin sodium (8.0 mg/ kg) administered subcutaneously every 14 days, and the introduction of a hypercaloric and hyperproteic diet.The animal died after 40 days, with severe cachexia, lethargy, dullness and signs of acute enteritis with severe diarrhea.Owners did not authorize the necropsy of the animal.

Discussion
The clinical history and symptoms in the affected cat were the same as the eight cases of feline idiopathic mural folliculitis  described in the literature, displaying generalized alopecia, erythema, crusting, hyperkeratosis and scarification of the face, pinnae, neck, and sequentially the trunk and limbs, as well as emaciation and apathy [3][4][5].The histopathological changes and also the mucin accumulation observed in the biopsies are consistent with the previous reported cases [3].On histopathological examination, sebaceous glands remained unchanged, which ruled out the possibility of feline sebaceous adenitis [6].Also, no atypia were identified in lymphocytic sequential histopathological examination, ruling out feline epitheliotropic lymphomas [1].No follicular parasites were detected and dermatophytosis was not found in fungal culture and with special staining for fungi performed during histopathology (PAS c/d).These findings are in accordance with other cases of feline idiopathic mural folliculitis described in literature [3,7].

First Case of Degenerative Mucinotic Mural Folliculitis in Brazil
Copyright: © 2016 de Sousa Filho et al.
of thymoma, which is a differential diagnosis for non-pruritic exfoliative dermatitis, with histopathological presentation of symptoms of lymphocytic mural folliculitis [8].
The animal examined in this case study was found to be positive in the ELISA test for the detection of antibodies against feline immunodeficiency virus, which may explain the severity of the case and the rapid deterioration of his clinical condition.The intense nuclear and cytoplasmic immunostaining of epithelial cells and mixed inflammatory infiltrate in the dermis and epidermis, the immunohistochemistry anti-FIV, strengthens the relationship of the disease with feline immunodeficiency virus.The cause of mucinotic mural folliculitis is still not clear.FIV should be investigated as a possible cause or comorbidity, given the severity when associated with this disease.Moreover, FIV infection has been reported in 3/7 cats with this disease [3].

Conclusions
Degenerative Mucinotic Mural Folliculitis should be included in the differential diagnosis of feline exfoliative dermatitis and alopecia.Early diagnosis through histopathological and immunohistochemical tests is extremely important in determining treatment, given the severity of the clinical condition.Sequential exams, including biopsies, X-rays and ultrasounds are required to follow the course of the disease, as well as to rule out other possible causes of mural folliculitis associated to cancer and parasitic infections.

Figure 1 :
Figure 1: (A) A 10-year-old male Siamese cat showing alopecia in the face, muzzle and pinnae region, neck, torso and limbs.(B) Presence of row crop cultivators, erythema, alopecia and severe facial edema.