Urticaria pigmentosa (also known as generalized eruption of cutaneous mastocytosis (childhood type): 616 
) is the most common form of cutaneous mastocytosis. It is a rare disease caused by excessive numbers of mast cells in the skin that produce hives or lesions on the skin when irritated. Signs and symptoms
Urticaria pigmentosa is characterized by excessive amounts of mast cells in the skin. Red or brown spots are often seen on the skin, typically around the chest, forehead, and back. These mast cells, when irritated (e.g. by rubbing the skin, heat exposure), produce too much histamine, triggering an allergic reaction that leads to hives localized to the area of irritation, sometimes referred to as Dariers sign. Severe itching usually follows, and scratching the area only serves to further symptoms. Symptoms can be mild (flushing and hives that require no treatment), moderate (diarrhea, tachycardia, nausea/vomiting, headache, and fainting), or life-threatening (vascular collapse requiring emergency treatment and hospitalization). Cause
The majority of urticaria pigmentosa cases are caused by a point mutation at amino acid 816 of the proto-oncogene c-kit. c-kit is a transmembrane protein which, when bound to Mast Cell Growth Factor (MCGF), signals the cell to divide. Mutations in position 816 of c-kit can result in a constant division signal being sent to the mast cells, resulting in abnormal proliferation. Different mutations have been linked to different onset times of the disease.
It is highly associated with NOTCH1 mutations.Other types include:

Large granular lymphocytic leukemia
Adult T-cell leukemia/lymphoma
T-cell prolymphocytic leukemiaIn practice, it can be hard to distinguish T-cell leukemia from T-cell lymphoma, and they are often grouped together. NK cell leukemia
Aggressive NK-cell leukemia (ANKL) is a lymphoid leukemia that is a deficiency NK cells. Not very much is known about this disease due to its rarity, but it is highly aggressive. Most patients will die within 2 years. Diagnosis
The requirements for diagnosing ANKL are as follows:
Immature-looking NK cells
Certain immunophenotypes
Germline configuration genes: TCR-β and IgH
Restricted cytotoxicityThe T-cell receptor (TCR) is an important factor when ANKL is being diagnosed along with T-cell leukemia. The TCR gene transcripts are normally positive for ANKL. Current Research is attempting to find the causation of ANKL. So far, the researchers have concluded that lineage of the T-cell receptor gene does not predict the behavior of the disease. Treatment
ANKL is treated similarly to most B-cell lymphomas. Anthracycline-containing chemotherapy regimens are commonly offered as the initial therapy. Some patients may receive a stem cell transplant. Most patients will die 2 years after diagnosis. Diagnosis
Flow cytometry is a diagnostic tool in order to count/visualize the amount of lymphatic cells in the body. T cells, B cells and NK cells are nearly impossible to distinguish under a microscope, therefore one must use a flow cytometer to distinguish them. Treatment
Targeted therapy
Several molecular tumor profiling protocols have been initiated in Europe (e.g., MOSCATO-01, iTHER, and ESMART) to identify actionable lesions for targeted treatment in specific subgroups of patients.