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Mastocytosis is a group of rare disorders of both children and adults caused by the presence of too many mast cells (mastocytes) in a person's body. more...

Mac Ardle disease
Macular degeneration
Mad cow disease
Maghazaji syndrome
Mal de debarquement
Malignant hyperthermia
Mallory-Weiss syndrome
Malouf syndrome
Marburg fever
Marfan syndrome
MASA syndrome
Mast cell disease
MAT deficiency
Maturity onset diabetes...
McArdle disease
McCune-Albright syndrome
Mediterranean fever
Megaloblastic anemia
Meleda Disease
Meniere's disease
Mental retardation
Mercury (element)
Metabolic acidosis
Metabolic disorder
Methylmalonic acidemia
Microscopic polyangiitis
Microtia, meatal atresia...
Miller-Dieker syndrome
Mitochondrial Diseases
Mitral valve prolapse
Mobius syndrome
MODY syndrome
Moebius syndrome
Molluscum contagiosum
MOMO syndrome
Mondini Dysplasia
Mondor's disease
Monoclonal gammopathy of...
Morquio syndrome
Motor neuron disease
Moyamoya disease
MPO deficiency
Mullerian agenesis
Multiple chemical...
Multiple endocrine...
Multiple hereditary...
Multiple myeloma
Multiple organ failure
Multiple sclerosis
Multiple system atrophy
Muscular dystrophy
Myalgic encephalomyelitis
Myasthenia gravis
Mycosis fungoides
Myelodysplastic syndromes
Myeloperoxidase deficiency
Myoadenylate deaminase...
Myositis ossificans


Mast cells are located in connective tissue, including the skin, the linings of the stomach and intestine, and other sites. They may play an important role in helping defend these tissues from disease. By releasing chemical "alarms" such as histamine, mast cells attract other key players of the immune defense system to areas of the body where they are needed.

Mast cells seem to have other roles as well. Because they gather together around wounds, mast cells may play a part in wound healing. For example, the typical itching you feel around a healing scab may be caused by histamine released by mast cells. Researchers also think mast cells may have a role in the growth of blood vessels (angiogenesis). No one with too few or no mast cells has been found, which indicates to some scientists that we may not be able to survive with too few mast cells.

Mast cells express a cell surface receptor termed c-kit (CD117), which is the receptor for scf (stem cell factor). In laboratory studies, scf appears to be important for the proliferation of mast cells, and inhibiting the tyrosine kinase receptor with imatinib (see below) may reduce the symptoms of mastocytosis.


Scientists first described urticaria pigmentosa in 1869. Systemic mastocytosis was first reported by scientists in 1936.


Chemicals released by mast cells cause changes in the immune system leading to typical allergy symptoms such as:

  • itching
  • abdominal cramping
  • and even anaphylaxis (shock from allergic or immune causes)

When too many mast cells exist in a person's body, the additional chemicals can cause:

  • Skin lesions
  • Abdominal discomfort
  • Diarrhea
  • Stomach ulcers
  • Episodes of very low blood pressure (including shock) and faintness
  • bone or muscle pain
  • Nausea and vomiting


Doctors can diagnose urticaria pigmentosa (cutaneous mastocytosis, see below) by seeing the characteristic lesions which are dark-brown and fixed. A small skin sample (biopsy) may help confirm the diagnosis.

By taking a biopsy from a different organ, such as the bone marrow, the doctor can diagnose systemic mastocytosis. Using special techniques on a bone marrow sample, the doctor looks for an increase in mast cells. Another sign of this disorder is high levels of certain mast-cell chemicals and proteins in a person's blood and sometimes in the urine.


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Bone density, bone markers and bone radiological features in mastocytosis
From Age and Ageing, 1/1/96 by Christer Johansson


Mastocytosis represents a spectrum of disease ranging from urticaria pigmentosa, an increase of dermal mast cells, to systemic mastocytosis involving bone marrow, skeleton, gastrointestinal canal, liver and spleen. Various skeletal manifestations have been observed in patients with mastocytosis [1] possibly reflecting different amounts of infiltrating mast cells and variation in the active substances they secrete. The major metabolite of histamine, methylimidazoleacetic acid in urine (MeImAA), is established as a good indicator of the mast cell mass in the body [2]. New methods of measuring bone density and bone markers such as osteocalcin [serum bone-Gla-protein (BGP)] have made it possible to detect failure in bone mineral turnover and remodelling. BGP is a vitamin Kdependent gamma-carboxylated protein synthesized by osteoblasts. It seems to be of importance in initiating mineralization and is regarded as a biochemical indicator of bone turnover. The aim of this study was to compare patients with systemic mastocytosis and with urticaria pigmentosa in regard to bone density and biochemistry.

Material and Methods

Patients: Sixteen adult patients, six men and ten women (mean age 50.8 years), with mastocytosis were included in the study. Six patients had systemic mastocytosis and ten had urticaria pigmentosa. Four patients (three men and one woman) with an increased number of mast cells in the bone marrow and increased excretion of the major histamine metabolite in urine had pronounced radiological manifestations in the skeleton. Substantial clinical and laboratory data are presented (Table I). The subjects participating in the study had no endocrine disorder and no therapy involving steroids, oestrogens, vitamin D, parathyroid hormone or calcium supplements.


The diagnosis of the skin disease was based on the clinical criteria for urticaria pigmentosa, e.g. multiple reddish brown maculae urticating after rubbing. The diagnosis of systemic mastocytosis was based on direct demonstration in bone marrow biopsy of an increased number of mast cells, marrow lesions containing mast cells, lymphocytes and eosinophils [3] and an increase in urinary excretion of methylimidazoleacetic acid [2]. Clinical data included measurement of the excretion of this major histamine metabolite in urine (Table I). Information about physical activity, tobacco-smoking habits, previous and present physical activity, previous fractures, age at menarche and menopause, number of pregnancies, consumption of milk, cheese, coffee and medications was obtained from a self-administered questionnaire.

Bone mineral measurements: Measurement of bone mineral density (g/[cm.sup.2]) for comparison with age-matched controls was performed in the distal right radius and ulna with singlephoton absorptiometry (SPA) with a radiation source of [sup.125.I] (Osteometer DT 100). In the hip, anterior/posterior spine and total body, the same calculations were made by dual-energy X-ray absorptiometry (DXA) (Lunar DPX, Lunar Radiation Corporation, Madison WI). The DXA-method of bone mineral measurement was described by Fogelman and Ryan [4]. As reference population we used data from a Danish study of 317 men and 1123 women aged 20-80 years randomly sampled from the local population register and measured at the Department of Clinical Chemistry, Glostrup Hospital, Denmark using the SPA-method as described by Christiansen et al.[5].

Biochemical methods: The urinary excretion of methylimidazoleacetic acid (MeImAA) was calculated as MeImAA mmol/mol creatinine [3]. Venous blood was sampled from an antecubital vein after a 30 minute rest in the sitting position. The subjects were asked to fast and not to smoke after 22 h 00 on the evening before the study. All individuals were treated by the same staff and by identical procedures. Serumosteocalcin (S-BGP) (reference interval 2-13,[mu]g/l) was determined by a double-antibody RUA method (International CIS, GIF-sur-Yvette Cedex, France). Serum alkaline phosphatase (S-ALP) (reference interval 0-5.0 [mu]kat/1), serum-tar/rate-resistant acid phosphatase (S-TRAP) (reference interval 0-60 nkat/l) were determined by standard methods [6]. Serum-insulin-like growth factor (IGF-13 (reference interval 0.34-1.9kU/l) was registered on three consecutive days in one patient with severe vertebral fractures (case 4). One patient (case 13) refused venepuncture.

Radiographs, body mass index, bone marrow biopsies and iliac crest bone biopsies: Radiographs of the spine (T4-L5) were assessed by a radiologist for evidence of vertebral fracture in 13 patients of the total 16 patients (three patients were excluded on account of young age and lack of severe symptoms). Anteroposterior and lateral view of the thoracic and lumbar spine were obtained at a standard target-to-film distance of 105 cm. Moderate vertebral fracture was defined as an anterior/posterior (A/P) vertebral height ratio of 0.66 or less. Severe vertebral fracture was defined as a loss of vertebral height of more than 33% at both the anterior and posterior edges compared with the posterior edge of an adjacent vertebral body. These criteria have been suggested as a standard to reduce overdiagnosis of vertebral fractures [7]. Body mass (of subjects wearing underwear only) and height were measured to the nearest 0.1 kg and 0.1 cm, respectively. Body mass index (BMI) was calculated as body weight divided by height squared [8]. Bone marrow from crest biopsies was taken from all 16 subjects with mastocytosis using the long toluidine-blue staining technique for mast cells [9] and May Grunewald Giemsa staining for smears of bone marrow.

Trans-iliac crest bone biopsies after tetracycline labelling [10] were performed with a Burchardt instrument in the two men with the most severe mastocytosis and vertebral fractures and a BMD in the hip of 2.5 SD below the norm in order to exclude osteomalacia. The bone specimens were fixed in 70% ethanol and dehydrated with alcohol in increasing concentrations. Undecalcified sections were cut after being dehydrated and embedded in methylmethacrylate. The samples were sectioned in a hard sectioning Jung microtome Model K. Sections 5 [mu]m thick were stained according to Goldner's modification of Masson tricome staining. For evaluation of in vivo tetracycline labelling, 20 [mu]m-thick sections were cut.

Statistical analysis: Associations were evaluated first by linear regression. Correlation coefficients and significance were calculated. Fisher's two-sided permutation test was used to assess differences between groups [11].


Case 2: A 35-year-old physically active professional cook had noticed pain in the back after heavy lifts and had radiographic evidence of severe vertebral compressions. The patient showed a bone density of 57% of age matched controls in lumbar spine and 61% in the hip (Figure 1) an increased number of mast cells in bone marrow at crest biopsy and moderately increased urinary excretion of MeImAA (Table I). Iliac crest bone biopsy revealed no osteomalacia but moderate osteoporosis with normal trabecular volume but decreased osteoid surfaces and osteoid volume and increased mineral apposition rate (Table II). Normal S-BGP and increased level of S-ALP pointed to high bone turnover and increased resorption verified by a level of 60 nkatal/l in S-TRAP.

Case 4: A 40-year-old physician had urticaria pigmentosa and severe back pain and vertebral fractures sustained after heavy lifts (Table I). Bone marrow crest biopsy showed a slight increase in the number of mast cells and excretion of MeImAA indicated systemic mastocytosis. The patient had a rapid progression of the vertebral deformity with several severe vertebral fractures and low bone density especially in trabecular bone in the lumbar spine (50% of age-matched controls) and in the right hip (75% of age-matched controls) (Figure 1). Iliac crest bone biopsy demonstrated increased osteoid area, normal apposition rate and the marrow showed a varied and active structure of cells but no osteomalacia (Table II). Normal levels of S-BGP but increased S-ALP suggested increased formation inadequately compensating for resorption (Table I). IGF-1 was registered on three consecutive days at 0.29, 0.31 and 0.31kU/1 (reference interval 0.34-1.9kU/I). This finding confirmed a low level of IGF-1 corresponding with a low degree of bone formation [12].

Authors' addresses C. Johansson, D. Mellstrom Department of Geriatric Medicine, Vasa Hospital, S-411 33 Goteborg, Sweden

G. Roupe Department of Dermatology,

G. Lindstedt Department of Clinical Chemistry,

Goteborg University, Sweden

COPYRIGHT 1996 Oxford University Press
COPYRIGHT 2004 Gale Group

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