1. Submitted to:- Dr. D.J. Ghodasara
Associate Professor,
Dept. of vet. Pathology, Anand
Submitted by:- Undhad Vishal
M.V.Sc. Scholar
Dept. of vet. Pathology

2. Mast cell
 Mast cell or mastocyte is a normal component of connective
tissue
 Mast cell are quite pleomorphic & nucleus are round or
ovoid & basophilic granules
 Cytoplasmic basophilic granules physiological active & two
components secretes
1. Histamine
2. Heparin

3. Mast cell
Eosinophile
Basophile

4. Mastocytoma/Mastoma in Dog
 Mastocytoma is benign tumor of tissue mast cells
German “mast” means fattend or stuffed
“cyte” comes from Greek “kytos” means hollow cell
Etiology
 Genetic predispose
 golden/red coat color
 Chronic immune over-stimulation that occurs in dogs with
allergies or other inflammatory conditions.
 There may be environmental factors, viruses or other
undetermined contributors.
 Middle age to older dogs are more likely to develop MCT's

5. Incidence
 6% of all tumors & 13% of skin tumors in dog
 Age:- 8 years
 Breed:- Boxer & Pug more common
 Sex:- Both sex same incidence
Clinical characteristics
 Gastric & duodenal ulcer
 Focal glomarulonephritis
 Defect in immune response
 Defective blood coagulation

6. Sites
 Hindquarter are most common (thigh, groin, scrotum)
Gross morphology
 1 to 10 cm diameter
 Tumor present in dermis
 Cut surface is grayish white
 Some time well capsulated grossly

7. FIGURE 1. A large pedunculated cutaneous mast cell tumor on a mixed-breed female dog.
FIGURE 2. female Shar-Peis at left hindlimb more aggressive and invasive mast cell
tumors with invole mammary tissues.
FIGURE 3. A hyperpigmented raised lesion involving the left lateral thigh region.
FIGURE 4. A raised erythematous mucocutaneous lesion involving the preputial orifice on
a castrated male pug.

8. A large and invasive mast cell
tumor involving the left tarsus in
a female Labrador
Mast cell tumor on the hock of a
6-year-old boxer

9. Mast cell tumor on left hind
limb of a dog
Large Mast cell tumor on the
right fore limb of a dog

10. Mast cell tumor on the inner thigh of a dog

11. Mast cell tumor of the paw
Mast cell tumor of the paw

12. Multiple cutaneous mast cell
tumors with peritumoral
edema and bleeding.

13. Preputial mast cell tumor with
peritumoral edema, bruising and
erythema.
Muzzle mast cell tumor.

14. Grade
I One tumor confined to the dermis without
regional lymph node involvement
II One tumor confined to the dermis with regional
lymph node involvement
III Multiple dermal tumors or large infiltrating tumor
with or without regional lymph node involvement
IV Any tumor with distant metastases or recurrence
with metastases

15. Cell
characters
Mature Intermediate Anaplastic
Cell shape Round to avoid Round to avoid Pleomorphic
Cell size Uniform Vary Vary
Cytoplasmic
border
Well defined Indistinct Indistinct
Nuclei Uniformly
spherical
Large, slight
vesicular
Large, vesicular &
irregular
Mitotic figures Rare Present Numerous
Cell arrangement Loosely in cord or
nest
Cord Large sheets

16.  Presents of eosinophiles due to some immunological
reaction
 Focal area of collagen degeneration are present
 Vascular lesion like hyalinization & fibrinoid degeneration
of small arterioles
 In 10% cases focal accumulation of lymphocyte & plasma
cells
Hematology
 Increase serum gamma globulin
 Rarely circulating mast cells

17. Growth & metastasis
 Least potentially malignant
 Correlation between degree of maturity of tumor &
eventual dissemination of neoplastic mast cells
 Internal dissemination of malignant tumor in following
organs regional lymph nodes, spleen, liver, kidneys,
lungs & heart
Prognosis
 It is estimated that 50% of surgically removed mast cell
tumors will re-grow in the same area.
 Prognosis is variable and depends on many factors
including tumor location, histological grade and clinical
stage

18. Jejunum of dog. Tumor cells are diffusely invading from the mucosal cell
layer to the serosa. Mucosal ulceration is visible with tumor cell
infiltration. HE.

19. Stomach of dog Slight pleomorphic tumor cells include round to ovoid
nuclei with some pleomorphism. Numerous mitotic figures are visible
(arrows). HE.

20. Monotonous population of mast cells with centrally located hyperchromatic
nuclei and few discernable cytoplasmic granules. (HE, 10X)

21. Boxer:-Mast cell tumor, well differentiated, Wright-Leishman stain. Well
differentiated mast cells have numerous, purple, cytoplasmic granules that
partially obscure nuclear morphology.

22. Cutaneous mast cell tumor (well differentiated), dog, Wright-Leishman
stain. The mast cells have numerous purple granules that partially
obscure nuclear morphology

23. Well differentiated mast cells, cutaneous neoplasm, dog, Wright-Leishman
stain. The neoplastic cells are of relatively uniform size and appearance with
numerous fine purple granules.

24. Well differentiated cutaneous mast cell tumor, dog, hematoxylin & eosin
stain. The mast cells have a relatively uniform appearance with heavy
cytoplasmic granulation.

25. Intermediate differentiation, cutaneous mast cell tumor, dog, hematoxylin
& eosin stain. The mast cells exhibit mild anisocytosis, anisokaryosis,
decreased granulation, and increased mitotic activity

26. Well differentiated cutaneous mast cell tumor, dog, AgNOR stain. The mast
cells have 1-2 AgNORs per cell with an overall score of 1.8. The potential
for metastasis is low.

27. Intermediate differentiation, cutaneous mast cell tumor, dog, AgNOR stain.
The mast cells have 1-7 AgNORs per cell with an overall score of 3.19. The
potential for metastasis is very high.

28. Intermediate differentiation of mast cells, cutaneous neoplasm, dog,
Wright-Leishman stain. The mast cells are large with pleomorphic
cytoplasmic granulation that varies in size and abundance.

29. Poorly differentiated mast cells, cutaneous neoplasm, dog, Wright-
Leishman stain. The mast cell (left) is large and has sparse cytoplasmic
granulation.

30. Boxer:-Mast cell tumor, poorly differentiated, Wright-Leishman stain.
The cytoplasm contains fine but sparse purple granules. A few eosinophils
also are present.

32. Treatment
 Surgery
 Radiation therapy
 Cryosurgery
 Photodynamic therapy
 Chemotherapy
-Corticosteroids like prednisolone
-Antihistaminic drugs
-antitumor drugs likes Vinblastine, vincristine

33. Mastocytoma in cat
 Two forms:-
1. Cutaneous/skin MCT
2. Histiocytic/visceral MCT
Incidence
 Second most common skin tumor (20% of all skin tumors)
 Age:- 10 years
 Breed:- Siamese cats
 Sex:- Male>Female
Sites & gross morphology
 Head & neck region more common
 Two type cutaneous growths:-
1. Firm
2. Diffuse

34. Multiple mast cell tumors in
the skin of a cat with the
visceral form of mast cell
tumor disease
Multiple mast cell tumors all
over their body

35. Histologic features
 Same to dog
 Some confusion between mastocytoma & eosinophilic
granuloma complex
 Skin & oral cavity diffuse infiltration of eosinophiles & some
extent mast cells in some lesions is called as eosinophilic
granuloma complex
Growth & metastasis
 Potentially malignant than dog
 50% primary cutaneous mastocytoma involvement of
regional lymph node & liver, spleen & other visceral organs

36. Haired skin of cat:- Endocytosis of erythrocytes
by neoplastic mast cells

37. Lymph node, cat, Wright-Leishman stain. Metastatic mast cells exhibit
anisocytosis and anisokaryosis with a variable degree of fine
metachromatic granulation.

38. Mastocytoma of horse
Classification & incidence
 Two distinct form
1. Single cutaneous nodule
2. Disseminated multiple focal mast cell lesion in skin
 Age:- 7years
 Sex:- Male > Female
 Breed:- No predispose
Site & gross morphology
 Any where in body but more in head
 2 to 20 cm diameter
 Tumor confined to skin
 Surface normal appearance, hairless or ulcerated

39. Histological features
 Variable sized aggregates of well differentiated mast cells
 Mitotic figures are rare
 Mature eosinophiles are local or diffuse accumulation
 Characteristic feature is focal area of necrosis contained
eosinophiles & necrotic debris
Etiology, transmission & metastasis
 Unknown
 Onchocerca spp. microfilariae
 No transmission occurs
 Metastasis not reported

40. Mastocytoma of cattle, Sheep & pig
Cattle
 3% Of all cutaneous & subcutaneous tumors
 No any age, breed & sex predilection
 1 to 10 cm diameter
 Aggregates of mast cell in regional lymph node, spleen,
liver, lungs, heart & kidneys
 Also occurs in internal organs ( omentum, abomasum,
tongue) without cutaneous involvement
 Microscopically similar to other spp.
Pig
 Age:- 6 to 18 month
 Limited to skin single or multiple
 No metastasis
Sheep
 Vary little information regarding mastocytoma

41. Mast cell leukemia/Mstosarcoma
 Primarily in cat with involvement of bone marrow, blood &
spleen
 Age:- >8years
 Sex:- Male>Female
 Splenomegaly (splenicmastocytosis), anemia, vomiting,
GIT hyperirritability
 Most notable gross lesion in cat are hugely enlarged
chocolate brown spleen, wider spread small pale focai on
liver, gastric & duodenal ulcer.
 Diagnosis based on presence of mast cell in smear from
blood & bone marrow
 Mast cell 20u in diameter & round, centrally or
eccentrically placed nucleus & cytoplasm packed with
small, uniform, purple granules

42. Spleen, dog, Wright-Leishman stain. Two metastatic mast cells with
coarse purple granules are present

43. Bone marrow, dog, Wright-Leishman stain. Metastatic mast cells exhibit
anisocytosis and anisokaryosis.

44. Blood smear, dog, mast cell leukemia, Wright-Leishman stain. Cutaneous
neoplasms were not present.

45. Blood smear, dog, Wright-Leishman stain. Mast cell is present in the
blood smear of a dog with cutaneous neoplasms.

46. Blood smear, dog, Wright-Leishman stain. A degranulated mast cell (right)
is present in the blood smear of a dog with systemic mastocytosis.