Mucinosis Flashcards
What are the two major groups of mucinosis?
- Primary cutaneous mucinoses (mucin deposition leads to clinical lesions and is the primary histologic feature)
- Secondary mucinosis: mucin deposition is an associated finding but not the primary process
What cell produces mucin?
Fibroblasts
What are the two major divisions of types of mucin in the dermis?
- Attached: glycosaminoglycans attached to a protein core (proteoglycan monomer). Dermatan sulfate, chondroitin sulfate
- Free: Hyaluronic Acid
What are the two major “attached” types of mucin?
Dermatan sulfate and chondroitin sulfate
What is the major “free” form of mucin in the dermis?
Hyaluronic acid
What are the two most common glycosaminoglycans in the dermis?
Chondroitin sulfate and hyaluronic acid (HA most important)
What condition is scleromyxedema associated with?
Paraproteniemia is almost always present and is IgGlambda (as compared to scleredema and NXG which are IgGk)
What is the clinical appearance of scleromyxedema?
Numerous firm waxy 2-3 mm closely aligned papules form in a widespread symmetrical pattern.
- Most common sites of involvement are the head and neck as well as upper trunk, hands, forearms, and thighs
The strikingly linear array often seen of the papules
What level of facial involvement can be seen with scleromyxedema?
Severe involvement can lead to leonine facies, however less robust involvement can occur near the glabella with furrowing.
note there is mucous membrane and scalp sparing
What is the Dermato-neuro syndrome sometimes seen in scleromyxedema?
Potentially life-threatening encephalopathy; abrupt worsening of skin lesions, flu-like prodrome, fever/seizure, unexplained coma
What are some of the systemic manifestations of scleromyxedema?
Proximal muscle weakness, dysphagia, coma, sensory peripheral neuropathy (older men), arthropathies, scleroderma-like renal dz, carpal tunnel syn, restrictive or obstructive lung dz.
What are the most common sites of visceral involvement of scleromyxedema?
1 = GI/esophagus (ask about swallowing) and #2 Lung
What is the treatment for scleromyxedema?
No good tx for it.
- Most accepted currently is IVIg +/- thalidomide, CS, or therapies for MM (2nd line)
- 3rd line could be autologous BMT
What distinguished localized lichen myxedematosus from scleromyxedema?
Lesions in localized lichen myxedematosus are localized to only the skin, localized the upper and lower extremities, sometimes trunk
- The pathology triad is not present, only mucin deposition with variable fibroblast proliferation
- There is no monoclonal gammopathy
What is the microscopic triad of scleromyxedema?
- Mucin deposition
- Fibroblast proliferation
- Fibrosis
What are the 4 types of localized lichen myxedematosus?
- Discrete papular form
- Acral persistent papular mucinosis
- Cutaneous mucinosis of infancy
- Nodular lichen myxedematosus
What is the clinical presentation of Discrete papular form of localized lichen myxedematosus?
- 2–5 mm papules on the extremities and trunk in a symmetrical pattern, face is spared
- No induration
- No systemic symptoms
What are the clinical features of the acral persistent papular mucinosis form of localized lichen myxedematosus?
- F:M = 3:1
- Ivory to skin-colored papules limited to dorsal hands and extensor forearms
- No systemic symptoms
Pathology findings of acral persistent papular mucinosis?
Discrete papule shape, collarette of scale, and then well-circumscribed deposits of abundant acid mucopolysaccharide between collage in the superficial dermis. Stains + with alcian blue, colloidal iron, or toluidine blue stains.
- Increased mast cells
What are the important clinical features of cutaneous mucinosis of infancy?
- Firm opalescent papules on neck, upper arms, trunk
- No systemic symptoms or spontaneous resolution
Clinical presentation of pure nodular forms of localized lichen myxedematosus?
Multiple nodules on limbs and trunk with mild or absent papular component.
What are the pathology findings of localized lichen myxedemotosus?
Mucin in the upper and mid reticular dermis, fibroblast proliferation is variable, fibrosis is not marked or absent.
- In the acral persistent form the mucin is more superficial and in the cutaneous mucinosis of infancy, the mucin is very superficial and can look enclosed by the epidermis.