Module 9: Lumps and Bumps (Week 12 & 13) Flashcards
Non- Neoplastic Nodular Dermatoses
Non- Neoplastic Nodular Dermatoses
Nodules are …
- > 1cm
- Firm
- Circumscribed
- Extends to deep layers of the skin:
- Dermis or subcutaneous tissue (large)
Nodular dermatoses:
- Neoplastic
- Infectious
- Bacterial (culture)
- Actinomyces => G(+), Opportunistic commensal flora of oral cavity and bowel, found in environment
- Anaerobic culture
- Nocardia => G(+), common soil saprophytes , filamentous
- Aerobic culture
- Mycobacteria => Aerobic, Rods, Non-motile =, Acid-fast
- Fresh tissue samples are important - Fungal
- Dermatophytosis (kerion)
- Cryptococcosis
- Blastomycosis
- Coccidioidomycosis
- Histoplasmosis
- Bacterial (culture)
- Sterile
- Cutaneous histiocytosis
- Sterile nodular panniculitis
- Sterile granuloma/pyogranuloma syndrome
For a single, acute nodule in a healthy animal, rule out:
- Foreign body => difficult to find, CT can be useful
- Trauma
- Secondary bacterial infection
- Kerion (deep dermatophytosis)
Many deep fungal infections will affect other organs, such as:
- LN
- Lungs
- Eye
- CNS
(T/F) Some deep bacterial and fungal infections can be zoonotic, and you have to be cautious
True
- Infection occurs from trauma and contamination of penetrating wounds
- It may take months to years for clinical signs to develop
Actinomycosis
- Immunosuppression may play a role in the development of chronic infections
- Most commonly isolated from non-healing wounds and abscesses
- Intra-abdominal and thoracic infections have been reported
Treatment for Actinomycosis:
- Surgical excision or debulking
- Penicillin/amoxicillin
- continue treatment at least 1 month after complete remission (3-4 months) - Relapses 15-42%
The following clinical signs are from …
- Cellulitis
- Ulcerated Nodules
- Draining tracts
- Lymphadenopathy
Nocardiosis
- affecting the base of the tail
- Likely due to fighting wounds
- Filamentous acid-fast on cytology
- Stain: Zielhl-Neelsen
What is the treatment for Nocardiosis?
- Surgical resection and antibiotics
- Potentiated Sulfas
- Combination therapy
- Minocycline/doxycycline
- Treat at least one month past the clinical cure
- Mycobacterium tuberculosis complex=> dermal nodules, lymphadenopathy, respiratory, GI
- M. tuberculosis
- M. bovis (bovine TB)
- M, microti (mice)
- Mycobacterium avium complex => cutaneous nodules, respiratory disease, disseminated disease
- M. avium (Mycrobacterium avium subsp. paratuberculosis is the microorganism responsible for causing Johne’s disease in farm animals)
- M. intracellulare
- M. avium (Mycrobacterium avium subsp. paratuberculosis is the microorganism responsible for causing Johne’s disease in farm animals)
Slow- Growing Mycobacteria
- Opportunistic
- Ubiquitous, free-living organisms found in soil and water
- Infections occur as a result of inoculation into tissue through wounds or contaminated surgical sites
Rapid-growing mycobacteria
Mycobacteria panniculitis
- Fatty tissue - feline inguinal fat pad often affected
- Flanks
- Base of tail
- SQ tissue becomes thickened and adheres to the dermis
- non-painful, non-pruritic, firm, or fluctuant nodules that ulcerate and spread outwards
*Distinct clinical presentation of *rapid-growing Mycobacteria**
Treatment:
- Antibiotic therapy immediately after surgery (or before)
- Fluoroquinolones - Enrofloxacin, marbofloxacin or pradofloxacin
- Localized nodular skin disease
- Cause: Fastidious mycobacterial species probably transmitted by biting insects
- Signs: single or multiple skin nodules commonly affecting the head and ears
Canine Leproid granuloma syndrome (CLGS)
- hasn’t been able to be culture
- Prognosis is good
Cryptococcosis
- Relatively small
- Nitrogen-rich alkaline enviroment
- Pigeon droppings - Common cause of nasal disease in cats
- Nitrogen-rich alkaline enviroment
Dogs: - eyes and CNS
Diagnosis:
- Clear or refractile halo
- Pyogramulomatous inflammation
Management for …
- Azoles antifungal for less severe cases (Itraconazole)
- 6-12 months are necessary to avoid recurrence
- Indications for discontinuing therapy:
- a stable low-level titer in a cat that has been asymptomatic for at least two months
- two negative titers three months apart
Cryptococcus
- ocular disease: poor prognosis
- Occurs in the soil in a mycelial form
- Mycotic pneumonia that can disseminate hematogenously throughout the body
- Dimorphic yeast
Blastomycosis
- Moist, acidic soil rich in organic material near bodies of freshwater
- Beaver dams - ideal
- endemic in OH
- respiratory signs
- The presence of respiratory signs in conjunction with draining skin lesions and/or uveitis in a young dog living in an endemic area should raise an index of suspicion for blastomycosis
- Broad base budding
- Itraconazole with no CNS involvement
- Soilborne fungus
- bird or bats
- Ohio river valleys
- inhalatiion of microconidia
- dimorphic, saprophytic soil fungus
- convert to yeast in lungs
- cats: disseminated disease (prognosis poor) -> lethargy, fever, anorexia, weight loss, and dyspnea
- dogs: infection can be confined to the respiratory or GI tract
- invasive fungal rhinitis
- serologic testing
- itraconazole
Histoplasmosis
- Moss and hay
- puncture wounds associated with thorns
- hunting dogs and intact cats
- zoonosis
- cutaneolymphatic forms most common
- disseminated form -> 1/3
- Itraconazole
Sporotrichosis
Sterile Nodular Dermatoses
Sterile Nodular Dermatoses
- affects only the skin
- etiology and pathogenesis is unknown
- immune-mediated
- is characterized by specific morphologic and immunohistochemistry criteria which help with diagnosis
- any age (3-9yrs)
- multiple hairless, erythematous dermal to subcutaneous nodules
- localized predominantly to the face, neck, nasal mucosa, perineum, scrotum, and feet
- non-pruritic or painful
- histopathology important, sterile granuloma and pyogranuloma syndrome
- 50% responded to prednisone as a sole therapy
- azathioprine, cyclosporine
- tetracycline
Cutaneous Histiocytosis
- inflammation of the subcutaneous fat and it may be associated with a variety of conditions
- refers to sterile inflammation of the subcutaneous fat tissue of unknown origin
- Sterile nodular panniculitis has been documented in association with
- Systemic lupus erythematosus
- Pancreatitis and pancreatic tumors
- Rheumatoid arthritis
- Lymphoplasmacytic colitis
- Single or multiple lesions
- normal skin color or erythematous or bluish in color
- some lesions regress while others develop draining tracts and become ulcerated
- associated with systemic disease
- suppurative to pyogranulomatous or granulomatous with fat droplets or cells present
- immunosuppressive drugs for multiple lesions
Sterile Nodular panniculitis
- is a less common disease
- papules, nodules or plaques
- idiopathic
- immune response against persistent endogenous or exogenous antigens
- dogs of any age affected
- great Dane, boxer, golden retriever, collie, dachshund, English bulldog, and Weimaraner
- firm, haired covered to partially alopecic, erythematous papules, nodules, or plaques
- Head and distal extremities more often
- Draining tracts and ulceration can be observed - paws
- rule out infection!
- immunosuppressive therapy
Sterile granuloma/pyogranuloma syndrome (SGPS)
