42: Mastocytosis Flashcards
(96 cards)
What is the hallmark of mastocytosis?
The hallmark of mastocytosis is the pathologic accumulation of mast cells in tissues.
What are the common cutaneous findings in children with mastocytosis?
Common cutaneous findings in children with mastocytosis include hyperpigmented macules, papules, or nodules, and diffuse infiltration of the dermis.
What is the significance of c-kit mutations in mastocytosis?
c-kit mutations, particularly in codon 816, are significant as they lead to amino acid substitutions and cause constitutive activation of KIT, which results in continued mast cell growth and development.
What cytokines are important in regulating mast cell growth and differentiation?
The important cytokines in regulating mast cell growth and differentiation include:
Cytokine | Function |
|———-|———-|
| IL-3 | Signal transduction pathways with SCF, minimal direct effects on proliferation |
| IL-4 | Enhances mast cell function in mature cultures |
| IL-6 | Increases mast cell mediator concentrations |
| IL-9 | Increases the number of mast cells in culture |
| IFN-gamma| Inhibits mast cell proliferation and influences phenotype and function |
What are the common extracutaneous tissues involved in mastocytosis?
The most common extracutaneous tissues involved in mastocytosis include the bone marrow, liver, spleen, and lymph nodes.
What is the typical age of onset for mastocytosis in children?
Most cases of mastocytosis arise in children, with 70% occurring by 6 months of age and 90% by the first 2 years of life.
How does mastocytosis present in children compared to adults?
In children, it typically presents with cutaneous findings such as hyperpigmented macules, papules, or nodules, and most children only have skin involvement. In contrast, adults are more likely to have systemic disease.
What role do c-kit mutations play in mastocytosis, particularly regarding codon 816?
Mutations in c-kit, specifically in codon 816, lead to amino acid substitutions that cause constitutive activation of KIT. This results in continued mast cell growth and development.
How do cytokines influence mast cell growth and differentiation in mastocytosis?
Cytokines play a crucial role in regulating mast cell growth and differentiation:
Cytokine | Effect on Mast Cells |
|———-|———————|
| IL-3 | Minimal direct effects on proliferation, important in early cultures |
| IL-4 | Enhances mast cell function in mature cultures |
| IL-6 | Increases mast cell mediator concentrations |
| IL-9 | Increases the number of mast cells in culture |
| IFN-gamma| Inhibits mast cell proliferation and influences phenotype and function |
What are the common clinical manifestations of cutaneous mastocytosis (CM) in children?
Children with cutaneous mastocytosis (CM) commonly present with urticaria pigmentosa (UP), which appears as tan to brown papules or macules, ranging from 1.0 to 2.5 cm in size.
What are the differences in cutaneous lesions between children and adults with mastocytosis?
The cutaneous lesions in children and adults with mastocytosis differ in size and appearance:
Age Group | Lesion Characteristics |
|———–|———————–|
| Children | Tan to brown papules and macules, 1.0 to 2.5 cm in diameter, often on the trunk. |
| Adults | Smaller reddish-brown macules and papules (approximately 5 mm or less), with variable hyperpigmentation and fine telangiectasias, most numerous on the trunk and proximal extremities. |
What is the significance of Darier sign in mastocytosis?
Darier sign is a reaction that occurs when skin lesions are scratched or rubbed, leading to urtication and erythema. This sign is readily demonstrated in childhood urticaria pigmentosa (UP) and mastocytomas.
What hematologic disorders are associated with systemic mastocytosis with associated clonal hematologic non-mast-cell-lineage disease (SM-AHNMD)?
Hematologic disorders associated with SM-AHNMD include:
- Polycythemia rubra vera
- Chronic myeloid leukemia
- Chronic myelomonocytic leukemia
- Idiopathic myelofibrosis
- Chronic eosinophilic leukemia
- Hypereosinophilic syndrome
- Acute and chronic lymphocytic leukemia
- Non-Hodgkin and Hodgkin lymphoma
What are the clinical manifestations of cutaneous mastocytosis (CM) in children, and how do they differ from those in adults?
In children, cutaneous mastocytosis (CM) is primarily manifested as urticaria pigmentosa (UP), which appears as tan to brown papules or macules, ranging from 1.0 to 2.5 cm in diameter. In contrast, adult cutaneous lesions are smaller (approximately 5 mm or less), reddish-brown macules and papules.
What is the significance of Darier sign in the context of mastocytosis?
Darier sign is a reaction that occurs when scratching or rubbing skin lesions leads to urtication and erythema. This sign is readily demonstrated in childhood urticaria pigmentosa (UP) and mastocytomas.
What hematologic disorders are associated with systemic mastocytosis with an associated clonal hematologic non-mast-cell-lineage disease (SM-AHNMD)?
Hematologic disorders associated with SM-AHNMD include:
- Polycythemia rubra vera
- Chronic myeloid leukemia
- Chronic myelomonocytic leukemia
- Idiopathic myelofibrosis
- Chronic eosinophilic leukemia
- Hypereosinophilic syndrome
- Acute and chronic lymphocytic leukemia
- Non-Hodgkin and Hodgkin lymphoma
A child presents with tan-brown nodules on the distal extremities that urticate upon rubbing. What is the likely diagnosis and its typical onset age?
The likely diagnosis is solitary mastocytomas, which are tan-brown nodules that frequently appear on the distal extremities. Their onset is generally before 6 months of age.
What explains the difference in lesional skin reactivity between children and adults with cutaneous mastocytosis (CM)?
Mast cell concentrations in mastocytomas and childhood urticaria pigmentosa (UP) are 150 to 40 fold greater than in normal skin, while in adult mastocytosis, mast cell concentrations are only 8 fold greater than controls.
What are the common symptoms and signs of mastocytosis?
Symptoms and signs of mastocytosis may include:
- Pruritus
- Flushing
- Diarrhea
- Abdominal pain
- Nausea
- Bloating
- Vomiting
- Gastric reflux
- Palpitations
- Dizziness
- Syncope
What are the potential triggers that can exacerbate symptoms of mastocytosis?
Symptoms of mastocytosis can be exacerbated by:
- Exercise
- Heat
- Local trauma to skin lesions
What is the significance of gastrointestinal (GI) symptoms in adults with mastocytosis?
GI symptoms in adults with mastocytosis range from 25% to 70%, with diarrhea being the most common symptom. This may result from gastric hypersecretion, increased motility, and/or malabsorption.
What is Diffuse Cutaneous Mastocytosis (DCM) and its characteristics?
Diffuse Cutaneous Mastocytosis (DCM) is seen almost exclusively in infants and may persist into adult life. The skin often has a peau d’orange appearance and yellowish-brown discoloration.
What are the common symptoms associated with mastocytosis, particularly in children with diffuse cutaneous mastocytosis (DCM)?
Symptoms may include pruritus, flushing, diarrhea, abdominal pain, nausea, bloating, vomiting, gastric reflux, palpitations, dizziness, and syncope.
How can trauma to mastocytomas affect systemic symptoms in patients?
Trauma to mastocytomas can lead to systemic symptoms such as flushing and hypotension.