Multicentric Histiocytosis in Young Chickens. Gross and Light Microscopic Pathology

Abstract

During 1991-94, tissue specimens from 262 young chicken carcasses condemned at slaughter contained novel multicentric proliferations of histiocytelike cells. These tissues had been submitted to the USDA FSIS Eastern Laboratory because of grossly enlarged spleens, livers, or kidneys. The spleens were two to three times normal diameter and contained miliary white or yellow 1-3-mm foci. Similar miliary foci were present throughout the enlarged livers and kidneys. Microscopic examination of these tissues revealed discrete circular nodules expanding splenic periarteriolar lymphoid sheaths, hepatic periportal nodules, and discrete perivascular and more diffuse interstitial nodules replacing renal tubules. Nodules also were present in the pancreas, bone marrow, proventriculus, and lung, with more diffuse infiltrates in intestinal lamina propria. The cells composing these nodules contained irregularly oval, folded, or pleomorphic nuclei and relatively abundant eosinophilic cytoplasm. Mitotic figures and pyknotic nuclei were common. These cells were interpreted to be histiocytes (tissue macrophages or dendritic cells) and did not resemble lymphocytes. These proliferating cells also did not resemble the cell population of commonly diagnosed lymphoid neoplasms of young chickens. No intralesional organisms were detected and polymerase chain reaction analysis failed to detect Marek's herpesvirus DNA or leukosis/sarcoma and reticuloendotheliosis proviral DNA.

Histopathological Characteristics of Spindle-cell Proliferative Disease in Broiler Chickens and Its Experimental Reproduction in Specific Pathogen-Free Chickens

“…Histopathologically, spindle-cell proliferative disease was similar to MH and HS, but clearly differed from MD, LL, RE and BLS [1-3, 5, 7, 9]. In lesions of MH and HS, the origin of the proliferating cells is the histiocyte [1,5,6]. Although we performed special staining and immunohistochemical examinations aimed at determining the origin of the proliferating cells of spindle-cell proliferative disease, we could not determine their origin.…”

“…Microscopically, MD is characterized by proliferation of various-sized lymphoid cells, whereas LL is characterized by follicular proliferation of uniform lymphoblastic cells [3,7]. Recently, multicentric histiocytosis (MH) [5,6] and histiocytic sarcomatosis (HS) [1] have been reported as similar diseases associated with enlargement of the liver and spleen. MH and HS resemble each other histopathologically, but clearly differ from MD and LL with respect to the origin of the proliferating cells [1,3,[5][6][7].…”

“…Recently, multicentric histiocytosis (MH) [5,6] and histiocytic sarcomatosis (HS) [1] have been reported as similar diseases associated with enlargement of the liver and spleen. MH and HS resemble each other histopathologically, but clearly differ from MD and LL with respect to the origin of the proliferating cells [1,3,[5][6][7]. Experimental induction of MH in broiler and specific pathogen-free (SPF) leghorn chickens has been reported [4].…”

Multi-centric histiocytosis: Experimental induction in broiler and specific pathogen-free leghorn chickens

“…Multi-centric histiocytosis (MH) is a lesion that is seen frequently in the visceral organs of slaughtered broiler chickens in the USA (Hall et al, 1995;Hafner et al, 1996;Hafner & Goodwin, 1997). Affected chickens have splenomegaly (enlarged two to four times normal) and hepatomegaly (enlarged to two times normal ).…”

“…Miliary 0.5-to 2-mm white-grey-yellow nodules are most commonly seen scattered throughout the spleen, liver and kidney. Microscopically, nodules are composed of histiocytic cells accompanied by variable numbers of plasma cells and lymphocytes that replace and displace otherwise normal portions of the spleen, liver, kidney, pancreas, proventriculus, lung, enteric mucosa and bone marrow (Hafner et al, 1996;Hafner & Goodwin, 1997). Furthermore, broiler carcasses with MH may show cutaneous and visceral pallor, and may be noticeably smaller than the carcasses of their unaffected ockmates.…”