Histiocytoma in Dogs

Histiocytoma in Dogs

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Overview of Histiocytoma in Dogs

A histiocytoma is an unsightly but benign skin tumor that tends to arise on the skin of young dogs. While young dogs (under three years of age) are more likely to get these (especially on the face and extremities), they can happen to dogs of any age in just about any location.

Technically, a histiocytoma is an abnormal proliferation of histiocytes in the skin. Histiocytes are cells that function as part of the immunological barrier against invaders that would attempt an “attack” on the skin. In the case of histiocytomas, the self-regulatory reproductive mechanism of these histiocytes is clearly in disarray.

Though they’re considered ugly by most owners’ standards, these masses are benign. In fact, if left untreated they’ll spontaneously resolve within two to three months or less.

Many closely related but far less benign conditions are referred to as histiocytic disorders. In dogs, these include malignant histiocytosis, cutaneous histiocytosis, systemic histiocytosis, histiocytic sarcoma and histiocytic lymphoma.

Though they share the same family, these histiocytic disorders are far more aggressive conditions. As a general rule, dogs who suffer histiocytomas are not considered predisposed to these diseases.

Any dog can be affected by these masses but some breeds are predisposed. Labrador Retrievers and Boxers are commonly represented but histiocytomas can also affect Shar Peis, Bulldogs, American Pit Bull Terriers, American Staffordshire Terriers,Scottish Terriers, Greyhounds, and Boston Terriers, among others.

Signs of a Histiocytoma in Dogs

Histiocytomas typically appear as small, solitary, hairless lumps, usually on the head, neck, ears, and limbs. In some uncommon cases (in the case of Shar peis, in particular), multiple masses may be present at the same time.

These masses are usually less than 2.5 cm in diameter and may or may not be red and ulcerated on their surface.

Diagnosis of Histiocytoma in Dogs

Cytology can be very helpful for initial diagnosis, but isn’t typically considered definitive. Observation of regression or full histopathology upon removal are usually required by way of achieving definitive diagnosis.

Treatment of Histiocytoma in Dogs

Histiocytomas are considered highly treatable skin masses. Though they will typically regress spontaneously within a couple of months, they don’t always do so quickly or completely enough for a veterinarian’s (or owner’s) comfort. In other cases, their appearance (gross or cytological) may begin to defy the standards for this tumor type.

Any deviation from the expectation that the mass in question will prove benign is sufficient inducement to remove it as soon as possible. This determination depends on the veterinarian’s assessment of the mass’s location, size, appearance, cytological appearance, and degree of local inflammation, among other possible factors, including the patient’s history (of past skin masses, for example).

What Does Having a Histiocytoma Cost?

Veterinary Cost Associated with Histiocytoma in Dogs – The cost of histiocytomas depends, to a large extent, on whether they’re surgically treated or not. This expense is typically relegated to the price of initial cytology (sometimes omitted), pre-anesthetic labwork, anesthesia, surgical excision (complete removal), and biopsy. A typical outlay usually ranges from $300 to $1,000, depending on the level of care elected (generalist vs. specialist) and the geographic locale.

Histiocytoma tumors are covered by pet insurance. Learn more about Pet Insurance.

Prevention of Histiocytoma in Dogs

There is no known means of prevention for histiocytomas. However, limiting the breeding dogs with a known hereditary predisposition to histiocytomas is doubtless of some assistance here.

References for Histiocytoma in Dogs

  • “Tumors with Histiocytic Differentiation”. The Merck Veterinary Manual. 2006.
  • Affolter, Verena K. (2004). “Histiocytic Proliferative Diseases in Dogs and Cats”. Proceedings of the 29th World Congress of the World Small Animal Veterinary Association. Retrieved 2007-04-29.
  • Bush, J.M. Gardiner, D.W. Palmer, J.S. Rajpert-DeMeyts, E. Veeramachaneni, D.N.R. Testicular germ cell tumours in dogs are predominantly of spermatocytic seminoma type and are frequently associated with somatic cell tumours. International Journal of Andrology. Volume 34, Issue 4pt2, pages e288–e295, August 2011
  • Cronin, Kim (Dec 2006). “Deciphering the histiocytic code”. DVM (Advanstar Communications): 1S–8S.
  • Dhaliwal RS, Kitchel BE, Knight BL, et al. Treatment of aggressive testicular tumors in four dogs. J Am Anim Hosp Assoc 35: 311-318; 1999.
  • Ginhoux F, Tacke F, Angeli V, Bogunovic M, Loubeau M, Dai XM, Stanley ER, Randolph GJ, Merad M (2006). “Langerhans cells arise from monocytes in vivo”. Nat. Immunol. 7 (3): 265–73. doi:10.1038/ni1307. PMID 16444257.
  • Grieco V, Riccardi E, Greppi GF, et al. Canine testicular tumours a study on 232 dogs. J. Comp Path 138: 86-89, 2008.
  • Kaim U, Moritz A, Failing K, Baumgärtner W (2006). “The regression of a canine Langerhans cell tumour is associated with increased expression of IL-2, TNF-alpha, IFN-gamma and iNOS mRNA”. Immunology 118 (4): 472–82. doi:10.1111/j.1365-2567.2006.02394.x. PMC 1782326. PMID 16764690.
  • Moore P, Schrenzel M, Affolter V, Olivry T, Naydan D (1996). “Canine cutaneous histiocytoma is an epidermotropic Langerhans cell histiocytosis that expresses CD1 and specific beta 2-integrin molecules”. Am. J. Pathol. 148 (5): 1699–708. PMC 1861573. PMID 8623937.
  • Morrison, Wallace B. (1998). Cancer in Dogs and Cats (1st ed.). Williams and Wilkins. ISBN 0-683-06105-4.
  • Raskin, R.E.; DeNicola, D. (2006). “Cytology of Neoplasia”. Proceedings of the North American Veterinary Conference. Retrieved 2007-04-29.
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