Exam 4 - Histiocytic Sarcoma Flashcards
what are the 2 main disease forms seen with histiocytic tumors?
- reactive histiocytosis - NOT neoplastic (autoimmune inflammation driven by T cells) - cutaneous or systemic
- neoplastic histiocytosis - histiocytes are truly neoplastic & drive the disease - cutaneous histiocytoma (benign), solitary histiocytoma (likes the elbows), & disseminated (acts like lymphoma)
T/F: histiocytic cancer is rare, and only 1% of tumors affect lymphoid tissue
true
what are your dendritic cells?
langerhan’s, kupffer, tissue antigen presenting cells, & macrophages
what are the different paths that may be taken from the common progenitor cell that results in the different forms of histiocytic tumors?
- common progenitor cell -> myeloid stem cell CD 34+ -> CD1+ CD14- = langerhans/dendritic cell = HISTIOCYTOMA (benign)
- common progenitor cell -> myeloid stem cell CD 34+ -> CD1- CD14+ -> HISTIOCYTIC SARCOMA CD1+CD11c+MHCII+CD4-Thy-Ecad- = REACTIVE HISTIOCYTOSIS (like lymphoma)
- common progenitor cell -> monoblast CD34- -> blood monocyte -> macrophage -> low CD1 expression, CD11c-CD11d+MHCII+ = HEMOPHAGOCYTIC HISTIOCYTIC SARCOMA WORST PROGNOSIS
what is hemophagocytic histiocytic sarcoma?
the worst type of histiocytic sarcoma - macrophages eat everything in the body (including RBC) - most animals don’t survive past 30 days
what dog breeds are the usual suspects for reactive histiocytosis?
flat coated retrievers
bernese mountain dogs
what are the stats on bernese mountain dogs getting cancer?
92% chance of getting cancer in their life
average life span of 6 years
what breed is worse than golden retrievers when it comes to getting cancer?
bernese mountain dogs
what is the lesion shown? what signalment of animal is often affected by it? where are they often seen?
reactive cutaneous histiocytosis - benign, diffuse aggregation of histiocytes in the skin
signalment - young to middle aged dogs with a possible male predilection
locations - head, pinna, scrotum, nasal planum, & mucosa
how is cutaneous histiocytosis diagnosed? how is it staged?
diagnosed - biopsy (want 2-3 samples, normal & abnormal junction), FNA is often difficult to distinguish between inflammation & granulomas
staging done even if cutaneous is suspected because it could be a worse prognosis if it is the systemic form - baseline blood work, chest rads, & lymph node aspirates (sternal lymph nodes drains skin of ventral chest/abdomen or cranial mediastinal lymph nodes if draining head & neck)
T/F: it is rare to have systemic histiocytosis that doesn’t involve the skin
true
what therapy is used for cutaneous histiocytosis?
tetracycline/doxycycline + niacinamide + vitamin e (helps the skin heal faster) = help suppress t-cell function & drive down the immune response
if that doesn’t work, can try steroids, chemo (lomustine most intense), etc - radiation for local lesions for dogs that are mostly in remission
what is the prognosis for cutaneous histiocytosis?
fair to guarded - spontaneous regression is possible, but chronic relapses & drug failures are common
euthanasia is done due to poor QOL
what breeds are predisposed to getting systemic histiocytosis?
bernese mountain dogs, rottweilers, golden retrievers, flat coated retrievers, & irish wolf hounds
what is systemic histiocytosis?
non-neoplastic disease of proliferating lymphocytes (autoimmune disease)
what animals are predisposed to getting systemic histiocytosis?
male, middle aged dogs
what common locations do we see systemic histiocytosis manifest?
subcutis, lymph nodes, bone marrow, liver, spleen, scrotum, lung, ocular tissue, & mucus membranes
T/F: the clinical signs seen in patients with systemic histiocytosis reflect the organs that are involved
true
what clinical signs are associated with systemic histiocytosis?
signs often wax & wane
anorexia, depression, weight loss, harsh breathing, & PU/PD (hypercalcemia)
what is the etiology of systemic histiocytosis?
dysregulation of the immune system - helper t cells
infiltration of lymphocytes DOES NOT indicate spontaneous regression in this disease!!!
what organ is most likely to be affected in cutaneous histiocytosis?
the liver (maybe spleen)
is PU/PD seen in systemic histiocytosis due to hypercalcemia of malignancy? why?
NO!!!
monocytes produce vitamin D analogue which drives calcium up!
does infiltration of lymphocytes indicate spontaneous regression in systemic histiocytosis? what about in a cutaneous histiocytoma?
systemic - NO!!!!
cutaneous histiocytoma - YES
how is systemic histiocytosis diagnosed? how is it staged?
biopsy - well differentiated benign histiocytomas, multinucleated giant cells, deep lesions in the skin, interstitial dendritic cells instead of langerhan’s (more superficial cell type)
staging - same as cutaneous form
