Nodular Diseases Flashcards
What causes a nodule or draining lesion?**
- Infectious
- Neoplastic
- STerile
What are skin nodules?
- Circumscribed solid elevations
Where can nodules be located?
- Epidermis
- Dermis
- SC tissue
What does it mean to be adnexal?
- Attached to a hair follicle
When to worry based on history about a nodule?
- When did you first notice the lesion?
- Any changes?
- Rate of growth (remember your signalment too!)
Physical findings that might suggest a nodule isn’t benign
- Poor margins
- Depth of lesion
- Systemic signs
- Manipulation alters the lesion
- Location on the body
Things to observe about a nodule:
- Location on body
- Location within the skin
- Alopecic or haired
- Is the surface ulcerated?
- What are the margins like? (Obvious transition between normal and abnormal skin or blurred?)
- Remember to consider your signalment (age, breed, sex)
WHen to worry based on cytologic findings about a nodule?
- Mitoses
- Hemorrhagic aspirate
Basic diagnostics for nodules
- FNA/cytology
- Histopathology
- Culture from biopsy (bacterial, fungal, mycobacterial)
He recommends taking a sample for FNA then for biopsy and culture at the same time)
What on cytology suggests infection?
- Pyogranulomatous inflammation
How do you diagnose sterile disease?
- Exclude infection and neoplasia
What are more common bacterial causes of single nodules?
- Staphylococcus
- Mycobacteria
- Nocardia/Actinomycosis
Clinical signs of staphylococcus
- Furunculosis
- Botryomycosis (chronic bacterial disease)
Etiology of canine leproid granuloma?
- Mycobacteria CLG
- Novel mycobacterial species that do not grow using standard methods
Where are lesions restricted with canine leproid granuloma?
- Head and pinnae
Diagnosis of canine leproid granuloma
- Demonstration of acid fast organisms on histopathology or cytology
Appearance of acral lick dermatitis?
- Raised ulcerated firm mass over the distal extremity
What causes acral lick dermatitis?
- Chronic licking
What breeds get acral lick dermatitis?
- Large breed dogs
Two rules of acral lick dermatitis?
- ALWAYS INFECTED
2. Secondary to something
Inciting causes of acral lick dermatitis?
- Allergies**
- infection
- Prior surgery
- Foreign body
- Arthritis
- Previous trauma
- Neoplasia
- Behavioral
Diagnosis of acral lick dermatitis?
- Scrape (demodicosis is a rule out)
- Cytology –> biopsy
- Culture (from biopsy; poor man’s culture is to prep with chlorhexidine, rinse with saline and squeeze contents)
- Radiography
- Look for an underlying cause!!**
Treatment of acral lick dermatitis
- Treat underlying infection with 4-6 weeks of systemic antibiotics based on culture
- Identify the underlying cause
- +/- behavior modification to break the cycle
Other treatment options for acral lick dermatitis
- Cryosurgery
- CO2 laser surgery
- Acupuncture
- Behavior consult
Fungal causes of nodules
- Dermatophyte
- Saprophytic fungi
- Pythium/lagenidium
- Sporotrichosis
- Blastomycosis
- Histoplasmosis
- Cryptoccosis
- Coccidioidomycosis
What is a kerion?
Dermatophyte furunculosis
Appearance of kerion
- Usually solitary nodule often on the face
What often causes kerions?
- Microsporum gypseum, a soil dermatophyte
- Often a history of the dog sticking its face in the dirt
What class of fungi are pythiosis/lagenidiosis?
- Oomycetes
- Aquatic plant pathogens
- Not true fungi but saprophyte
Where is pythiosis or lagenidiosis found?
- Decaying wood and vegetable matter
Where is pythiosis or lagenidiosis typically found?
- Gulf coast states
- WI, NJ, VA, CA, AZ KY have had diagnoses
Cytology of pythiosis or lagenidiosis?
- Pyogranulomatous with eosinophils
- Hyphae hard to see
Biopsy of pythiosis or lagenidiosis?
- Silver stain required for Pythium
- Hyphae may invade blood vessels
- Granulomatous to pyogranulomatous dermatitis with eosinophils
- Hyphae may be found intracellularly in giant cells
- Hyphae are broad, thick-walled, and irregularly septate
- Hyphae of Lagenidium are larger than those of P. insidiosum
Other diagnostic tests for pythiosis or lagenidiosis?
- Culture
- Serology, PCR, IH
- In addition to the cytology and biopsy
Clinical signs of pythiosis?
Areas in contact with stagnant water most likely to be infected
- Lesions are usually solitary draining nodules on the lower extremities
Breed with increased incidence of pythiosis?
- German SHepherds
- Lesions in cats and horses described too
Lagenidiosis - where have cases been identified?
- FL, LA, TX, TN, and IN
Clinical signs of lagenidiosis?
- Same as those described for pythiosis
- Often quite aggressive
What is important to differentiate pythiosis and lagenidiosis (oomycetes) from?
- Zygomycosis (true fungal infections)
Culture of pythiosis/llagenidiosis?
- Isolation is difficult
- Requires production of sexual reproductive structures for species ID, which is tough
- Pythium can be identified on biopsy with immunoperoxidase technique
PCR and Pythium/Lagenidium
- Can identify Pythium and differentiate it
Is serology better for pythiosis or lagenidiosis?
- Pythiosis
- AGID and ELISA
Treatment of pythiosis/lagenidiosis?
- Very difficult
- WIde surgical excision treatment of choice**
- Systemic therapy (itraconazole +/- terbinafine) for 2-4 months
- <25% response
- Agriculture fungicides (Caspofungin or Mefenoxam)
- Immunotherapy with anti-pythium vaccine
Dermatologic manifestation of Blastomycosis?
- little nodules
Appearance of blastomycosis on cytology or biopsy
- Characteristic halo
Skin lesions with histoplasmosis?
- Papular to nodular growths often located at the mucocutaneous junctions
Appearance of histoplasmosis on cytology or biopsy?
- See them within macrophages
Cryptococcosis appearance classic?
- Bulging of the hea and bridge of the nose
Appearance of Cryptococcus
- Capsule
What causes viral warts?
Papilloma virus
Who gets viral warts?
- young dogs
Where do viral warts occur often?
- Around oral mucosa
Treatment for viral warts
- Regress on their own (within ~3 months)
- Azithromycin
- Laser surgery
Why can viral warts recur?
- For the virus to take place, there has to be a penetrating trauma
- Goes directly to the basal cell layer and invades the immune system
- Carries with it the viral particle and grows little roots
- has a little stalk
Cell type origin of histiocytomas
- Langerhans cell origin
What are proposed theories for what a histiocytoma is?
- Tumor vs reactive hyperplasia
Who gets histiocytoma?
- Common in young dogs
- Rare in cats
Clinical appearance of histiocytoma?
- Rapid growth
- Dome-shaped
- Alopecic
- 0.5 cm-1.5 cm
- May ulcerate
Clinical behavior of histiocytoma?
- Spontaneous regression in 1-3 months
- Often looks worse just before remission
Locations of histiocytomas?
- Head, pinna, limbs, scrotum
Treatment for histiocytoma?
- Ignore or remove
- Surgically remove if it’s removing them
Diagnosis of histiocytoma
- Signalment
- Clinical appearance
- Cytology shows round cells (Histiocytes with mitoses or lymphocytes in regressing lesions)
- Histopathology
Five differentials for round cells?
- Lymphoma
- Mast cell Tumor
- TVT
- Histiocytoma
- Plasmacytoma
What is cutaneous histiocytosis?
- Nodular disease of dogs
Where do nodules occur with cutaneous histiocytosis?
- Dermis or SC fat of face, neck, back and trunk
- May also occur in the nasal mucosa resulting in respiratory stridor
Appearance of nodules with cutaneous histiocytosis?
- ERythematous and nodular (raised)
Treatment of cutaneous histiocytosis
- Immunosupression (prednisone or dexamethasone)
- Doxycycline/niacinamide
- Cyclosporine
- Long term treatment usually needed
Histopath with cutaneous histiocytosis?
- Infiltrates of large histiocytic cells
What is a melanocytoma?
- Benign neoplasm from melanocytes
Who gets melanocytoma?
- Dogs, higher incidence in pigmented breeds
- Rare in cats
Locations of melanocytoma
- Trunk
- Head (eyelids, muzzle)
- Extremities (between digits)
Clinical appearance of melanocytoma?
- Solitary
- Circumscribed
- Alopecic
- Non-ulcerated
- Dome-shaped
- Blue-black to dark brown in color
Clinical behavior of most melanocytomas?
- Most are benign
- Can’t always predict based on histopathology
Diagnosis of melanocytoma
- Cytology and histopathology
Treatment of melanocytoma?
- Surgical removal with clean margins
What is the cell type for trichoblastoma (basal cell tumor)?
- Primitive hair germ epithelium
Who gets trichoblastoma?
- Common in dogs and cats
What is the most common pigmented tumor of cats?
- Trihoblastoma
Where do dogs get trichoblastomas?
- head and neck
Where do cats get trichoblastomas?
- Cranial half of the trunk
Clinical appearance of trichoblastoma
- SOlitary
- Dome-shaped
- Firm
- 1-2cm
- Alopecic
- Ulcerated
- Melanotic
Clinical behavior of trichoblastoma
- Benign
Treatment of trichoblastoma
- Observe
- Surgical excision (curative)
Sebaceous gland tumors in dogs vs cats - how common?
- Common in dogs
- Uncommon in cats
What are the four types of sebaceous gland tumors and relative rarity of each?
- Nodular sebaceous hyperplasia (most common)
- Sebaceous adenoma (common)
- Sebaceous epithelioma (common but often ulcerates and bleeds)
- Sebaceous adenocarcinoma (rare)
Location of sebaceous gland tumors
- Trunk
- Limbs
- Eyelids
- head
CLinical appearance of sebaceous gland tumors
- Wart-like or cauliflower like
- Pinkish to orangish
- may be melanotic or ulcerated
Clinical behavior of sebaceous gland tumors
- Benign
- new adenomas or hyperplasias will develop if you might complicate them?remove
- Adenocarcinoma and epithelioma rarely metastasize
What can happen to sebbaceous gland tumors that might complicate them?
- Can become colonized with Malassezia or bacteria
- Can be pruritic
- ID with surface cytology***
- Address the infections with topical treatments
Diagnosis of sebaceous gland tumors
- Clinical appearance usually
- Cytology
- Histopathology (suspicious of epithelioma or adenocarcinoma)
Treatment of sebaceous gland tumors
- Observe
- Surgically excise
When might you be more suspicious that it’s a sebaceous adenocarcinoma?
- Usually more ulcerated and inflamed with poorly defined borders
What is the doctor word for a skin tag?
- Acrochordon
What is a nevus?
Hamartoma
Treatment for acrochordon
- Single ones can be lasered off or excised, but if there are a lot it would take a very long time
What is a follicular hamartoma?
- Hairy mole
Perianal adenoma?
- Looks like a smooth, alopecic mass in the perianal region
Which category of nodules do many syndromes fit?
- Sterile
What is the most likely pathogenesis of sterile nodules?
- Most likely immune-mediated, but the pathogenesis is truthfully unknown
How do you diagnose sterile causes?
- Exclusion!
What are some dfdx for pyogranulomatous inflammation?
- Infectious until proven otherwise
- Could be sterile
How do you determine if pyogranulomatous inflammation is infectious or not?
- Negative tissue cultures
- No organisms seen on histopathology
- Lack of response to abx
Treatment recommendations for sterile disease?
- Long duration of therapy
- Doxycycline (niacinamide)
- Immunosuppressive steroids - prednisone or dexamethasone
- Cyclosporine
- Once in remission, slow taper over several months
What to do if something you suspect is sterile disease stops improving?
- Repeat cytology +/- biopsy and cultures
Dfdx for sterile nodules?
- Eosinophilic furunculosis
- Juvenile cellulitis
- Sterile nodular panniculitis**
- Sterile pyogranuloma/pyogranuloma syndrome
- Follicular cysts
- Perianal fistulas
- metatarsal fistulas
What is most likely cause of eosinophilic furunculosis?
- Arthropod or insect bite most likely
Onset of canine eosinophilic furunculosis
- Sudden
Treatment of canine eosinophilic furunculosis
- Often steroid responsive
Recurrence of canine eosinophilic furunculosis
- Rare
Who gets juvenile cellulitis?
- Young puppies usually, but may occur in adult dogs
- Dachshunds, Goldens, Pointers often
Appearance of juvenile cellulitis?
- Pustular to nodular disease of young puppies
When does juvenile cellulitis tend to occur?
- Following recent vaccination
What is the cause of juvenile cellulitis
- Unknown
- It does occasionally develop following recent vaccination, but attempts to reproduce the disease with a vaccine or virus have failed
Clinical signs of juvenile cellulitis
- Pustular to nodular disease
- Primarily affects face and head, especially muzzle and periocular region
- Ears, anus, and prepuce may also be affected
- Crusting on the muzzle (with a nodule underneath)
- Often a LARGE submandibular lymphadenopathy
- Occasionally sterile abscess at the site of vaccination
- reports of this occurring with HOD
Treatment for juvenile cellulitis
- Immunosuppression (but usually need concurrent ABs)
- Doxycycline/niacinamide
- Cyclosporine
- Slowly taper off meds once in remission
Diagnosis of juvenile cellulitis
- really needs a biopsy
- Remember you need to rule out infectious causes!
Sterile nodular panniculitis characteristics of disease
- Solitary or multiple SC nodules that ulcerate and discharge an oily, bloody exudate
- Lesions occur anywhere
Clinical signs of sterile nodular panniculitis
- Dogs may be systemically ill (anorexia, lethargy, fever)
- Serum alkaline phosphatase may be elevated (liver process or pancreatitis associated?)
Who is predisposed to sterile nodular panniculitis?
- Dachshunds, Maltese
Treatment for sterile nodular panniculitis
- First rule out infection with cytology/culture/biopsy
- Immunosuppression
- Doxycycline/niacinamide
- Cyclosporine
- Vitamin E
- can sometimes taper off all meds once in remission
Dermatologic lesions with sterile nodular panniculitis
- Solitary or multiple deep-seated cutaneous nodules
- Frequently ulcerate and discharge and will leak blood yexudate
- Lesions vary in locaiton and size, with majority occurring over the ventral lateral chest, neck, and abdomen
- Dogs may appear systemically ill with decreased appetite, lethargy, and fever
Major dfdx for sterile nodular panniculitis
- Bacterial or fungal infection
- Need to rule out with cytology, histopathology, and sterile cultures
What is sterile histiocytic disease?
- Periadnexal multinodular granulomatous dermatosis
- Sterile pyogranuloma/granuloma syndrome
Derm lesions with periadnexal multinodular granulomatous dermatitis
- Pyogranuloma/granuloma syndrome
- Multiple nodules of the head, pinna, and paws
Histopathologic pattern of periadnexal multinodular granulomatous dermatitis
- Characteristic
- Histiocytes
Treatment of periadnexal multinodular granulomatous dermatitis
- Immunosuppression
- after ruling out bacterial and fungal disease
- Steroid responsive at immune suppressive doses
- Some may respond to cyclosporine, doxycycline/niacinamide
Follicular cyst/epidermal inclusoin cyst appearance
- Dermal nodules sometimes within a pore
- Thick material inside (brown/gray thick per disease; toothpaste like)
Complications of follicular cyst/epidermal inclusion cyst
- Can create inflammatory reaction if ruptured
- Can become secondarily infected
Diagnosis of follicular cyst/epidermal inclusion cyst
- Biopsy
Treatment of follicular cyst/epidermal inclusion cyst
- Surgical excision (must pull out the lining of the cyst to be curative)
- Retinoids/Vitamin A?
- Could ignore
- Sudden occurrence of many nodules - rule out endocrine!
What is intracutaneous cornifying epithelioma?
- Form of follicular cyst or epidermal inclusion cysts
- Usually multiple and can be quite large
- Treat with surgical incision
Which breeds get intracutaneous cornifying epithelioma?
- Keeshonds and German Shepherds
Appearance of apocrine cysts, and what happens if you pop it?
- Fluid cyst
- Will fill back up if deflated
- Need to remove it to prevent recurrence
Appearance of perianal fistulas or anal furunculosis?
- Draining lesions around the anus
- Shallow, blind-ended sinuses
- Not associated with anal sacs
- Often very painful
Breed predisposition for perianal fistulas?
- German SHepherds or Irish Setters
Etiology of Perianal Fistulas
- Likely immune-mediated but full mechanism not well-elucidated
Clinical signs of perianal fistulas
- Clinical signs
- Cytology
- +/- biopsy (often quite painful and can’t suture well)
- Rectal examination (check for anal sac involvement)
Treatment for perianal fistulas
- Cyclosporine (+/- ketoconazole)
- Tacrolimus (better tissue penetration)
- Prednisone
- Food trial
- Antibiotics
Prognosis for perianal fistulas
- Good for control
Surgery for perianal fistulas?
- Reserved for refractory cases or with secondary anal sac involvement
Who gets focal metatarsal fistulas?
- German Shepherds
- Also reported in Weimaraner, Greyhound, Doberman
Clinical signs of focal metatarsal fistulas
- Asymptomatic to lame
Cause of focal metatarsal fistulas
- Unknown
Treatment of focal metatarsal fistulas
- Response to immunosuppression
- Steroids
- Tacrolimus
- Cyclosporine
- Doxycycline/niacinamide
