Twenty-six cases of Erdheim-Chester disease have been reported since it was first described in 1930 [1, 2] . The typical pathologic feature is an infiltration of foamy, lipid-laden histiocytes and giant cells [3] . Characteristic skeletal radiographic abnormalities are symmetric osteoblastic changes with or without lytic components in the major long bones, especially the diaphysis and metaphysi...

Malignant histiocytosis (MH) is a rare hematologic malignancy, especially in the first decade of life. The disease is clinically characterized by fever, hepatosplenomegaly, lymphadenopathy, pancytopenia and jaundice, and histologically by systemic proliferation of malignant histiocytes and hemophagocytosis. The prognosis is poor and often the diagnosis is not made before death. Because of ...

A previous publication documented a sarcomatous transformation observed in cell line derived from rat lymphoma growing monolayer culture. (9) The morphological and cytogenetic changes found, suggested the presence of virus differentiation malignant lymphoblasts toward histiocytes present paper describes, under electron microscope structural features original tumor, cells culture sarcoma. This s...

A 51-year-old man with a history of recurrent primary cutaneous marginal zone lymphoma involving his back returned for a follow-up visit at our cutaneous lymphoma clinic. He complained of a several-month history of a new asymptomatic papule on the mid-thoracic back. He denied fevers, chills, night sweats or fatigue. Clinical examination identified a 3 to 4 mm red to orange-colored papule on the...

We report 3 cases of a previously uncharacterized form of histiocytosis presenting in early infancy and showing ALK immunoreactivity. The patients presented with pallor, massive hepatosplenomegaly, anemia, and thrombocytopenia. Liver biopsy showed infiltration of the sinusoids by large histiocytes with markedly folded nuclei, fine chromatin, small nucleoli, and voluminous lightly eosinophilic c...

Benign cephalic histiocytosis (BCH) is a rare type of non-Langerhans histiocytosis with features of many small yellow, yellow-red, or yellow-brown papules located on face, head, neck, and shoulders of infants and young children. There would be no associated symptoms. The histopathological images reveal infiltration of histiocytes in dermis; immunohistochemically, the histiocytes are positive fo...

Spindle cell pseudotumors may occur due to mycobacterial infection in immunocompromised hosts, particularly those with acquired immunodeficiency syndrome (AIDS). Most of the reported mycobacterial spindle cell pseudotumors were found in the lymph nodes. We report a case of spindle cell pseudotumor in a 37-year-old man with AIDS who presented with a firm nodule over his right arm. Histologically...

Malakoplakia is a characteristic inflammatory condition, which is usually seen in the urogenital tract, and less frequently in the gastrointestinal tract. We present a case of colonic malakoplakia in an immunocompromised patient. A 55-year-old female visited the outpatient clinic for routine cancer surveillance. Her past medical history was significant for kidney transplantation 11 years ago, a...

Malakoplakia is a rare form of chronic granulomatous inflammation in mammals, and usually affects the urinary tract in humans. In this report, we present a case of granulomatous nephritis consistent with malakoplakia in a 4-year-old male cynomolgus monkey. Gross examination showed that the kidney was markedly enlarged and adhered to the surrounding organs. Histology showed that there was diffus...