User login
At birth, this child had a lesion on his shoulder that now—a year later—has doubled in size. His parents report no systemic symptoms or medication use for their son. They say that the child exhibits no distress; he does not attempt to scratch at the affected patch of skin. However, they observe that if the lesion is touched, it swells and then (within minutes) returns to normal.
There is no family history of similar problems. However, both the patient and his mother are highly atopic.
EXAMINATION
The lesion—a low, orange, oval plaque—measures about 3.5 x 2 cm. Barely palpable, it urticates when stroked with a fingernail edge but does not appear to cause any discomfort.
No other lesions of note are found. The child appears quite healthy and is in no distress.
What is the diagnosis?
DISCUSSION
Mastocytosis is caused by a localized accumulation of mast cells (a type of white blood cell) and CD34-positive mast cell precursors, which are normally present but widely scattered and sparse. This child has the most common form of cutaneous mastocytosis, which can manifest with solitary lesions or with dozens or hundreds of scattered lesions (the latter known as urticaria pigmentosa). Both types are typically benign and self-limited.
When stroked, mast cell lesions degranulate portions of the cell, releasing histamine precursors and leukotrienes (eg, IL 1 and IL 31). In most cases, stroking merely leads to short-lived urtication. But if the problem is more widespread (eg, urticaria pigmentosa) and the lesions are sufficiently traumatized, the release of these substances can lead to problems such as hypotension, malaise, fever, and abdominal pain.
Fortunately, this is rare, as is systemic mastocytosis—a condition in which mast cells infiltrate internal organs and bone marrow, interrupting normal function and, in the extreme, leading to mast cell leukemia. Our patient is not at risk for these complications; his lesion should resolve completely by age 3.
The differential for this patient’s lesion includes congenital nevus, lichen aureus, and café au lait spot.
TAKE-HOME LEARNING POINTS
- Cutaneous mastocytosis manifests as a reddish orange maculopapular patch, which urticates upon forceful stroking.
- Stroking the lesion degranulates the mast cells comprising it, leading to the release of histamine precursors.
- Mast cells can infiltrate internal organs and bone marrow, leading, in the extreme, to mast cell leukemia.
- Urticaria pigmentosa is a variation of mastocytosis in which hundreds of such lesions develop all over the body.
At birth, this child had a lesion on his shoulder that now—a year later—has doubled in size. His parents report no systemic symptoms or medication use for their son. They say that the child exhibits no distress; he does not attempt to scratch at the affected patch of skin. However, they observe that if the lesion is touched, it swells and then (within minutes) returns to normal.
There is no family history of similar problems. However, both the patient and his mother are highly atopic.
EXAMINATION
The lesion—a low, orange, oval plaque—measures about 3.5 x 2 cm. Barely palpable, it urticates when stroked with a fingernail edge but does not appear to cause any discomfort.
No other lesions of note are found. The child appears quite healthy and is in no distress.
What is the diagnosis?
DISCUSSION
Mastocytosis is caused by a localized accumulation of mast cells (a type of white blood cell) and CD34-positive mast cell precursors, which are normally present but widely scattered and sparse. This child has the most common form of cutaneous mastocytosis, which can manifest with solitary lesions or with dozens or hundreds of scattered lesions (the latter known as urticaria pigmentosa). Both types are typically benign and self-limited.
When stroked, mast cell lesions degranulate portions of the cell, releasing histamine precursors and leukotrienes (eg, IL 1 and IL 31). In most cases, stroking merely leads to short-lived urtication. But if the problem is more widespread (eg, urticaria pigmentosa) and the lesions are sufficiently traumatized, the release of these substances can lead to problems such as hypotension, malaise, fever, and abdominal pain.
Fortunately, this is rare, as is systemic mastocytosis—a condition in which mast cells infiltrate internal organs and bone marrow, interrupting normal function and, in the extreme, leading to mast cell leukemia. Our patient is not at risk for these complications; his lesion should resolve completely by age 3.
The differential for this patient’s lesion includes congenital nevus, lichen aureus, and café au lait spot.
TAKE-HOME LEARNING POINTS
- Cutaneous mastocytosis manifests as a reddish orange maculopapular patch, which urticates upon forceful stroking.
- Stroking the lesion degranulates the mast cells comprising it, leading to the release of histamine precursors.
- Mast cells can infiltrate internal organs and bone marrow, leading, in the extreme, to mast cell leukemia.
- Urticaria pigmentosa is a variation of mastocytosis in which hundreds of such lesions develop all over the body.
At birth, this child had a lesion on his shoulder that now—a year later—has doubled in size. His parents report no systemic symptoms or medication use for their son. They say that the child exhibits no distress; he does not attempt to scratch at the affected patch of skin. However, they observe that if the lesion is touched, it swells and then (within minutes) returns to normal.
There is no family history of similar problems. However, both the patient and his mother are highly atopic.
EXAMINATION
The lesion—a low, orange, oval plaque—measures about 3.5 x 2 cm. Barely palpable, it urticates when stroked with a fingernail edge but does not appear to cause any discomfort.
No other lesions of note are found. The child appears quite healthy and is in no distress.
What is the diagnosis?
DISCUSSION
Mastocytosis is caused by a localized accumulation of mast cells (a type of white blood cell) and CD34-positive mast cell precursors, which are normally present but widely scattered and sparse. This child has the most common form of cutaneous mastocytosis, which can manifest with solitary lesions or with dozens or hundreds of scattered lesions (the latter known as urticaria pigmentosa). Both types are typically benign and self-limited.
When stroked, mast cell lesions degranulate portions of the cell, releasing histamine precursors and leukotrienes (eg, IL 1 and IL 31). In most cases, stroking merely leads to short-lived urtication. But if the problem is more widespread (eg, urticaria pigmentosa) and the lesions are sufficiently traumatized, the release of these substances can lead to problems such as hypotension, malaise, fever, and abdominal pain.
Fortunately, this is rare, as is systemic mastocytosis—a condition in which mast cells infiltrate internal organs and bone marrow, interrupting normal function and, in the extreme, leading to mast cell leukemia. Our patient is not at risk for these complications; his lesion should resolve completely by age 3.
The differential for this patient’s lesion includes congenital nevus, lichen aureus, and café au lait spot.
TAKE-HOME LEARNING POINTS
- Cutaneous mastocytosis manifests as a reddish orange maculopapular patch, which urticates upon forceful stroking.
- Stroking the lesion degranulates the mast cells comprising it, leading to the release of histamine precursors.
- Mast cells can infiltrate internal organs and bone marrow, leading, in the extreme, to mast cell leukemia.
- Urticaria pigmentosa is a variation of mastocytosis in which hundreds of such lesions develop all over the body.