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RESUMEN La enfermedad de Rosai-Dorfman cutánea (ERDC) es una rara proliferación reactiva de histiocitos, que cursa con lesiones cutáneas sin compromiso generalizado. Las manifestaciones clínicas cutáneas son diversas y la variante clínica "tipo tumoración" es la forma más infrecuente. Se describe el caso de un paciente con ERDC que se presentó con esta forma inusual.
ABSTRACT Cutaneous Rosai-Dorfman disease (CRDD) is a rare reactive histiocytic proliferation, which presents with skin lesions without systemic involvement. The clinical cutaneous manifestations are diverse and the "tumor-like" clinical variant is the most infrequent. We describe the case of a patient with CRDD who presented with this unusual form.
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ABSTRACT First described by J Rosai and R F Dorfman in 1969, Rosai-Dorfman disease (RDD) is a benign, self-limiting histiocytosis of unknown etiology. It is usually seen in the first two decades of life. The most frequent clinical presentation is painless, bilateral cervical lymphadenopathy accompanied by fever, weight loss, and an elevated ESR. However, RDD without nodal involvement is extremely rare, and the most common extranodal location is the head and neck region, mainly affecting the nasal cavity, pharynx, and paranasal sinuses. Oral location of RDD is occasional; according to our knowledge, only 17 cases of oral Rosai-Dorfman disease without lymph node involvement have been found in the literature. Because of the rarity of these isolated oral presentations, the clinical and radiological aspects need to be more studied. This article aims to present a rare case of oral Rosai-Dorfman disease without nodal involvement, detail the clinical and radiological signs, and the treatment strategy used in our patient.
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RESUMEN Introducción: La enfermedad de Rosai-Dorfman es una histiocitosis linfática masiva caracterizada por emperipolesis con inmunohistoquímica positiva para S100 y CD68. Es una entidad clínica rara y de curso benigno más comúnmente presentada en varones. Objetivo: El propósito de este caso clínico es demostrar el tratamiento exitoso de la enfermedad de Rosai-Dorfman con inmunomoduladores y quimioterapia metronómica. Presentación del caso: Paciente masculino de 57 años que acude por linfadenopatía cervical bilateral, a quien se le realiza tomografía y biopsia ganglionar con resultados positivos para S100 y CD68 con marcado fenómeno de emperipolesis. Recibió esquema inmunomodulador y quimioterapia metronómica exitosa con remisión de enfermedad. Conclusiones: Los pacientes diagnosticados con Rosai-Dorfman son muy pocos debido a lo inusual de esta entidad clínica. Es importante mencionar que esta enfermedad es una histiocitosis de células tipo No Langerhans con características de benignidad y buena respuesta al manejo con corticoides y quimioterapia metronómica, terapia instaurada en nuestro paciente con buena evolución.
ABSTRACT Introduction: Rosai-Dorfman disease is a massive lymphocytic histiocytosis characterized by emperipolesis with positive immunohistochemistry for S100 and CD68. It is a rare clinical entity of benign course most commonly presenting in males. Objective: The purpose of this clinical case is to demonstrate successful treatment of Rosai-Dorfman disease with immunomodulators and metronomic chemotherapy. Case presentation: A 57-year-old male patient presenting with bilateral cervical lymphadenopathy underwent CT scan and lymph node biopsy with positive results for S100 and CD68 with marked emperipolesis phenomenon. He received immunomodulatory scheme and successful metronomic chemotherapy with disease remission. Conclusions: Patients diagnosed with Rosai-Dorfman are very few due to the unusual nature of this clinical entity. It is important to mention that this disease is a non-Langerhans cell histiocytosis with benign characteristics and good response to management with corticosteroids and metronomic chemotherapy, therapy established in our patient with good evolution.
Subject(s)
Humans , Male , Middle AgedABSTRACT
The Rosai-Dorfman disease (RDD) is a bening entity, of unknown etiology, rare, characterized by the overproduction of histiocytes and their subsequent accumulation in the lymph nodes, which may also compromise other organs and systems. It predominantly affects young people. The histological study, which shows emperipolesis, is very indicative but not pathognomonic, but with the immunohistochemistry the diagnosis of the disease is reached, which does not have a well-protocolized treatment. Its evolution is highly variable, with spontaneous remission being a possibility, although in some cases the commitment is extensive, compromising important or vital anatomical structures that requiere vigorous treatment, which can be surgical, radiotherapy and even chemotherapy. We present a case of RDD that affected a 17-year-old girl with upper jaw and right maxillary sinus commitment, which began with loss of teeth, and subsequent appearance of a painless and deforming facial tumour that underwent surgical resection. In this case, the etiological diagnosis was not posible in the preoperative period despite multiple biopsies. An extensive review of the literature is carried out in order to a better understanding of this pathology.
La Enfermedad de Rosai-Dorfman (ERD) es una entidad benigna, de etiología desconocida, poco frecuente, caracterizada por la sobreproducción de histiocitos y su posterior acúmulo en los linfonodos, pudiendo comprometer también a otros órganos y sistemas. Afecta predominantemente a personas jóvenes. El estudio histológico, que muestra emperipolesis, es muy orientativa pero no patognomónica, aunque con la Inmunohistoquímica se llega al diagnóstico de la enfermedad que no tiene un tratamiento bien protocolizado. Su evolución es muy variable, siendo la remisión espontánea una posibilidad, no obstante, en algunos casos, el compromiso es extenso, comprometiendo estructuras anatómicas importantes o vitales que requieren de un tratamiento enérgico, pudiendo ser éste quirúrgico, radioterápico y aún quimioterápico. Se presenta un caso de ERD que afectó a una joven de 17 años, con compromiso de maxilar y seno maxilar derecho, que debutó con pérdida de piezas dentarias y posterior aparición de un tumor facial indoloro y deformante que fue sometido a resección quirúrgica. En este caso no fue posible el diagnóstico etiológico en el preoperatorio pese a múltiples biopsias. Se hace una extensa revisión de la literatura con el objeto de conocer mejor esta patología.
Subject(s)
Humans , Female , Adolescent , Maxillary Diseases/surgery , Maxillary Diseases/diagnostic imaging , Histiocytosis, Sinus/surgery , Histiocytosis, Sinus/diagnostic imaging , Tomography, X-Ray Computed , Histiocytosis, Sinus/complications , Histiocytosis, Sinus/pathology , EmperipolesisSubject(s)
Humans , Female , Child , Purpura, Thrombocytopenic, Idiopathic , Megakaryocytes , EmperipolesisABSTRACT
Rosai-Dorfman disease (RDD) is an uncommon benign histiocytic disorder. It is found worldwide and slightly more common among in men (1.4:1), affecting individuals are with an average age of 20.6 years. Extranodal tissue involvement is documented in 25-43% of RDD patients. Here authors are discussing a case of 16-year-old male patient with the complaint of a single swelling over left forearm since one month with no lymphadenopathy. Radiology showed anechoic collection within the muscle and superficial to it. On microscopy, smear showed diffusely distributed histiocytes with cytoplasm showing intact lymphocytes with halo surrounding it (emperipolesis), without atypia. Based on cytomorphology diagnosis of Extranodal Rosai Dorfman Disease was made.
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Objective@#To explore the clinical manifestations, histopathological features, diagnosis, treatment and prognosis of Rosai-Dorfman′s disease (RDD) in the maxillofacial region and to review the relevant literature in order to improve the understanding, diagnosis and treatment of oral and maxillofacial RDD.@*Methods @#The clinical manifestations, histopathological features, diagnosis, treatment, and prognosis of a patient with RDD in the maxillofacial region admitted to Shenzhen People′s Hospital were analyzed, and the literature was reviewed for analysis. @*Results@#The clinical manifestations were palpable masses of 3.5 cm × 2.0 cm × 1.0 cm in the right cheek and 3.0 cm × 2.0 cm × 1.0 cm in the right submaxillary area, with clear boundaries, good mobility, medium and hard textures, respectively, no tenderness, smooth surfaces, and no obvious nodules. On contrast-enhanced and plain CT scans of the maxilla and neck, a diffuse soft tissue shadow was seen in the right maxillofacial region with an unclear boundary and uniform density, and the contrast-enhanced scan also showed moderate and uniform enhancement. The primary diagnosis was right maxillofacial lesions. The tumor was resected surgically. The pathological report was right buccal and right submaxillary extranodal RDD. Under light microscopy, nodular lesions in the fibrous fat tissue were found, which were composed of light and deep staining areas. The light staining areas consisted of patchy, polygonal cells with large volumes and rich cytoplasm, in which lymphocytes and neutrophils could be seen stretching into the movement; the deep staining areas were composed of lymphocytes and plasma cells. IHC: S-100 (+), CD68 (+), CD163 (+), CD1a (-), CD21FDC (+), langerin (-), IgG (+), IgG4 (+). No recurrence was found 11 months after the operation. RDD is a rare, benign and self-limited tissue and cell disease and consists of multiple lesions in the maxillofacial region. Its imaging features are similar to those of lymphoma. Its pathological features are large volumes, rich cytoplasm and phagocytosis of lymphocytes and plasma cells. Generally, RDD only needs to be observed, and individuals with symptoms or the involvement of important organs need to be treated; the first choice for the extranodal type is drug treatment, with radiotherapy administered if the central nervous system is involved. Surgery is recommended if involvement of important organs and compression of the trachea are observed; chemotherapy should be used for diffuse RDD. Most patients with RDD experienced relapse or remission of the disease; a few patients died because of the involvement of important organs or complications.@*Conclusion @#The clinical manifestations of maxillofacial RDD vary and lack specific imaging features, and pathological immunohistochemistry is the gold standard for diagnosis. The etiology is not completely clear, the treatment methods are varied, and the prognosis is related to the involved range of the disease.
ABSTRACT
Emperipolesis is the hallmark finding for Rosai-Dorfman disease. Till now many studies in literatures have shown emperipolesis as a finding in other benign as well as malignant conditions. Very few cases of malignant lymphoma have this phenomenon. Herewith, we put forward a rare case of lymphoma with clinical presentation showing involvement of spleen, liver, lymph nodes as well as lleo-cecal region. Light microscopy revealed large to medium sized lymphoid cells with intervening plenty of histiocytes showing evidence of emperipolesis that mimics Rosai Dorfmann disease. Due to atypical clinical presentations we thought of lymphoma as a differential diagnosis. Further immunohistochemistry was performed using histiocytic as well as lymphoid markers. To our surprise, it turns out to be Non Hodgkin Lymphoma with extensive emperipolesis which is extremely rare in thorough literature search. This case is presented due to its unique clinical as well as histological presentations.
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Histiocytosis is an uncommon disease characterized by excessive accumulation of histiocytes. Here, we report a rare case of non-Langerhans-cell histiocytosis in a 51-year-old woman who presented with severe symptoms of pericardial effusion. Radiologic investigation also detected multiple bone (lower limbs, vertebrae, ribs, and ilium) lesions. Resected pericardium showed abundant mono- or multi-nucleated non-foamy histiocytes (CD68⁺/CD163⁺/S-100⁺/CD1α⁻/langerin⁻) in a fibroinflammatory background. The histiocytes demonstrated emperipolesis of lymphocytes, a hallmark feature of Rosai-Dorfman disease (RDD). However, molecular analysis revealed a BRAF V600E mutation of the proliferating histiocytes, highlighting the neoplastic features frequently observed in another non-Langerhans-cell histiocytosis known as Erdheim-Chester Disease (ECD). We consider this case to be a unique presentation of ECD harboring some RDD-like cells with emperipolesis, but not a case of RDD with a BRAF mutation concerning its clinical manifestation (involvement of the heart and bones) and neoplastic features.
Subject(s)
Female , Humans , Middle Aged , Emperipolesis , Erdheim-Chester Disease , Extremities , Heart , Histiocytes , Histiocytosis , Histiocytosis, Non-Langerhans-Cell , Histiocytosis, Sinus , Lymphocytes , Pericardial Effusion , Pericardium , Ribs , SpineABSTRACT
Rosai-Dorfman disease (RDD), formerly called sinus histiocytosis with massive lymphadenopathy, is a non-neoplastic proliferative histiocytic disorder with behavior ranging from highly aggressive to spontaneous remission. Although the lymph nodes are more commonly involved, any organ can be affected. This study aimed to describe the features and the follow-up of a case of extranodal RDD. Our patient was a 39-year-old woman who was referred with an 11-month history of pain in the right maxilla. On clinical examination, some upper right teeth presented full mobility with normal appearance of the surrounding gingiva. Radiographic exams showed an extensive bone reabsorption and maxillary sinus filled with homogeneous tissue, which sometimes showed polypoid formation. An incisional biopsy demonstrated a diffuse inflammatory infiltrate rich in foamy histiocytes displaying lymphocytes emperipolesis. Immunohistochemistry showed positivity for CD68 and S-100, and negativity for CD3, CD20, and CD30. Such features were consistent with the RDD diagnosis. The patient was referred to a hematologist and corticotherapy was administrated for 6 months. RDD is an uncommon disease that rarely affects the maxilla. In the present case, the treatment was conservative, and the patient is currently asymptomatic after 5 years of follow-up.
Subject(s)
Humans , Female , Adult , Histiocytosis, Sinus/drug therapy , Histiocytosis, Sinus/pathology , Maxilla/pathology , Rare Diseases/diagnosisABSTRACT
Abstract: Rosai-Dorfman disease is a benign histiocytic proliferative disorder of unknown etiology. The disease mainly affects lymph node tissue, although it is rarely confined to the skin. Here, we describe a 53-year-old woman with purely cutaneous Rosai-Dorfman disease. The patient presented with a large pigmented plaque on her left leg, and sparse erythematous papules on her face and arms. A complete clinical response was achieved with thalidomide, followed by recurrence at the initial site one year later. The histological examination displayed the typical features of Rosai-Dorfman disease in the recent lesions but not in the older lesions. In the setting of no lymphadenopathy, the histopathological features of Rosai-Dorfman disease are commonly misinterpreted. Therefore, awareness of the histological aspects present at different stages, not always featuring the hallmark microscopic signs of Rosai-Dorfman disease, is particularly important for a correct diagnosis of this rare disorder.
Subject(s)
Humans , Female , Adolescent , Skin Diseases/pathology , Histiocytosis, Sinus/pathology , Arm , Antigens, Differentiation, Myelomonocytic/metabolism , S100 Proteins/metabolism , Antigens, CD/metabolism , Diagnosis, Differential , Histiocytes/pathology , LegABSTRACT
La enfermedad de Rosai-Dorfman; también conocida como linfadenopatía masiva con histiocitosis sinusal; es un raro desorden de etiología desconocida; generalmente asociado a un agrandamiento de los ganglios linfáticos superficiales y/o profundos. La mayoría de los pacientes no requiere tratamiento. Presentamos el caso de un niño de 10 meses de vida, que ingresa con una tumoración cervical izquierda de 25 días de evolución.
Rosai-Dorfman disease, also known as sinus histiocytosis with massive lymphadenopathy, is a rare dis order of unknown etiology, generally associated with enlargement of superficial and/or deep lymph nodes. Most patients do not require treatment. We report the case of a 10 month old infant who was admitted with a left cervical tumor of 25 days duration.
Subject(s)
Humans , Male , Infant , Histiocytosis, Sinus/diagnosis , Uterine Cervical Neoplasms/diagnosis , Hypertrophy , Lymph Nodes/pathologyABSTRACT
Rosai-Dorfman disease (RDD) is a benign proliferative histiocytic disorder of unknown etiology, which typically manifests as lymphadenopathy and systemic symptoms. Lymph node involvement is typical, but soft tissue RDD without nodal or systemic involvement is extremely rare. We report on a case of soft tissue RDD in a 16-year-old girl with a palpable mass on her buttock. It was firm, mobile, and discrete without tenderness. Excisional biopsy was performed, then RDD was confirmed histologically. RDD is a non-neoplastic disease that should be considered in the differential diagnosis of other soft tissue tumors. While the optimal treatment for extranodal RDD remains controversial, surgical excision is typically curative.
Subject(s)
Adolescent , Female , Humans , Biopsy , Buttocks , Diagnosis, Differential , Emperipolesis , Histiocytosis, Sinus , Lymph Nodes , Lymphatic DiseasesABSTRACT
Rosai-Dorfman disease is a benign, self-limited, idiopathic proliferative histiocytic disorder. It was first described in 1969 by Rosai and Dorfman. In its typical form the disease is characterized by extensive cervical lymphadenopathy associated with fever, polyclonal gammopathy and leukocytosis with neutrophilia. The skin is the most common site affected. Extranodal manifestations have been reported in 43% of cases. In this study, we report an atypical case of Rosai-Dorfman disease in a female with massive cutaneous manifestation on the thigh, associated with a minimal lymphadenopathy limited to the regional inguinal lymph nodes.
A doença de Rosai-Dorfman é uma desordem benigna, autolimitada, idiopática, decorrente da proliferação de histiócitos. Foi descrita pela primeira vez por Rosai e Dorfman em 1969. Tipicamente, a doença se caracteriza por extensa linfadenopatia cervical, febre, gamopatia monoclonal e leucocitose com neutrofilia. Manifestações extranodais são encontradas em 43% dos casos, sendo a pele o sítio extranodal mais comumente afetado. No trabalho, apresentamos um caso de doença de Rosai-Dorfman com apresentação cutânea exuberante na coxa direita e discreto comprometimento linfonodal limitado à cadeia regional.
Subject(s)
Female , Humans , Middle Aged , Histiocytosis, Sinus/pathology , Skin Diseases/pathology , Skin/pathology , Biopsy , ThighABSTRACT
Se presenta una paciente de 50 años de edad con lesión tumoral redondeada, no dolorosa en región inguinal, con crecimiento progresivo y formación de una placa eritematosa, con áreas de pigmentación e infiltración de tejidos profundos, así como aparición de otras lesiones de aspecto tumoral. El estudio anatomopatológico evidenció un infiltrado histiocitario con fenómenos de linfohistiofagocitosis (emperipolesis) y el inmunohistoquímico mostró positividad para vimentina, S-100, CD68 y lisozima. Se revisó la evidencia científica disponible en la literatura mundial para determinar las manifestaciones clínicas más frecuentes, así como los medios diagnósticos más empleados en la actualidad y el tratamiento de esta enfermedad. Es importante considerar a la enfermedad de Rosai-Dorfman cutánea como un posible diagnóstico para lo que es indispensable un profundo estudio de la biopsia, así como la realización de estudios de inmunohistoquímica, dada la benignidad y buen pronóstico que la caracterizan
A 50 year-old patient with a painless round tumoral lesion on inguinal region with progressive growth and formation of an eritematous plaque with areas of pigmentation, infiltration of deep tissues and apparition of other lesions with tumoral aspect is described. The anatomopathological study showed a hystiocitic infiltrate with linfohystiofagocitosis phenomenon (Emperipolesis) and the immunohystochemical made evident positive for Vimentine, S-100, CD68 and Lisozime. The available scientific evidence of the international literature was reviewed to determine the most frequent clinical manifestations of this disease, as well as most updated means of diagnosis employed and the treatment of this disease. It is important to consider the cutaneous Rosai-Dorfman disease as one of the possible diagnosis so a profound study of the biopsy is essential, as well as the immunohystochemical studies due to the mildness and good prognosis of this disease
Subject(s)
Humans , Female , Adult , Histiocytosis, Sinus , Case ReportsABSTRACT
La enfermedad de Rosai-Dorfman corresponde a una enfermedad rara con menos de 1.000 casos reportados. Sus características clínicas corresponden a un aumento de volumen en ganglios cervicales, sin embargo, presenta compromiso extranodal como única manifestación entre el 25 por ciento y 50 por ciento de los casos. La ubicación nasosinusal ha sido reportada previamente, pese a ello, es más frecuente encontrarla en otras ubicaciones. El diagnóstico se basa en el estudio histopatológico encontrándose el fenómeno de emperipolesis, con células positivas a la proteína S-100. Esta enfermedad es frecuentemente confundida con neoplasias malignas, por lo que debe ser reconocida y sospechada. Se presenta el caso de un paciente de 15 años con historia obstrucción nasal de larga data, con múltiples recurrencias de la enfermedad de Rosai-Dorfman, demostrada mediante histopatología.
The Rosai-Dorfman disease corresponds to a rare disease with less than 1,000 reported cases. Their clinical characteristics correspond to a volume increase in cervical nodes, There is an extranodal involvement as the only manifestation of between 25 percent percent and 50 percent percent of cases. The sinonasal location has been previously reported. Diagnosis is based on histopathology with the phenomenon of emperipolesis with cells positive for S-100 protein. This disease is often confused with malignancy, so it must be recognized and suspected. A case of a patient 15 years with a history of longstanding nasal obstruction, with multiple recurrences of Rosai-Dorfman disease, demonstrated by histopathology.
Subject(s)
Humans , Male , Adolescent , Histiocytosis, Sinus , Nasal Obstruction/etiology , Diagnosis, Differential , Nasal Obstruction/surgery , RecurrenceABSTRACT
Relata-se o caso de uma paciente com doença de Rosai-Dorfman cutânea que apresentava na região glútea direita uma placa eritemato-acastanhada infiltrada com áreas amareladas e pápulas eritemato-acastanhadas perilesionais. O exame anatomopatológico revelou infiltrado inflamatório predominantemente de linfócitos e histiócitos de citoplasma amplo, claro e contendo células inflamatórias íntegras (emperipolese). Nenhuma outra alteração ao exame físico e laboratorial foi encontrada. A doença de Rosai-Dorfman é uma forma rara de proliferação histiocitária e o acometimento estritamente cutâneo é ainda mais raro. Sua etiologia é desconhecida e a correlação clinicopatológica permitiu o diagnóstico dessa enfermidade.
We report a patient with cutaneous Rosai-Dorfman disease that presented on the right buttock, a red brown plaque with yellowish areas and red-brown satellite papulas. The histopathologic exam revealed inflammatory infiltrate predominantly of lymphocytes and histiocytes with wide and clear cytoplasm containing intact inflammatory cells (emperipolesis). Any other alteration in the physical exam and laboratorial was not found. The Rosai-Dorfman disease is a rare form of histiocytic proliferation and the strictly cutaneous form is still rarer. The aetiology is unknown and the clinical and histologic correlation enables the correct diagnosis.
Subject(s)
Humans , Female , Middle Aged , Histiocytosis, SinusABSTRACT
Rosai-Dorfman Disease (RDD) or Sinus Histiocytosis with massive lymhadenopathy (SHML) is a rare, benign proliferative disorder of histiocytes, sometimes showing familial incidence. It is mainly characterized by painless bilateral cervical lymph node enlargement and is often associated with fever and leucocytosis. It presents in the first or second decades of life, though any age group can be affected. Without the awareness about RDD, the diagnosis of RDD is unexpected especially in South East Asian Countries where certain lymphadenopathies such as tuberculosis, metastatic nasopharayngeal carcinoma and lymphomas are common. RDD is commonly missed and so its revision would seem worthwhile, this case illustrating the disappearance of the lymphadenopathy without treatment.
ABSTRACT
Liver tissuses obtained from 5 human fetuses between 11 weeks and 23 weeks of gestation during the high activity of hepatic hemopoiesis were observed with transmission electron microscope using continuous series of thin sections. The objective of present study was to evaluate ultrastructures of megakaryopoietic cells, the migration of extravascular megakaryocyte into the sinusoidal lumen and the relevence between a migrated megakaryocyte and a Kupffer cell. Immature megakaryocytes were usually observed between growing hepatic laminae and within hepatic sinusoids. A megakaryoblast contained numerous polyribosomes, rather large mitochondria, short tubular elements of rough endoplasmic reticulum and small granules. Moreover, demarcation tubules and a few small specific granules were observed in immature megakaryocytes. The nucleus was mononuclear but frequently indented. With maturation, the nuclei were multilobulated. In the cytoplasm, in contrast to the decrease in polyribosomes and rough endoplasmic reticulum, the numerous specific granules and well -developed demarcation membrane system were predominant. Thereafter cytoplasmic zonation was observed clearly in maturing and mature megakaryocytes. Some megakaryocytes passed through the sinusoidal lining epithelium and into the hepatic sinusoids. The cell to cell interaction was often found as adhesion between migrated megakaryocyte and Kupffer cell, and erythroblasts within megakaryocyte (emperipolesis). These results suggest that intravascular megakaryopoiesis in addition to extravascular megakaryopoiesis occurs to produce platelet during the human fetal liver.
Subject(s)
Humans , Pregnancy , Blood Platelets , Cell Communication , Cytoplasm , Emperipolesis , Endoplasmic Reticulum, Rough , Epithelium , Erythroblasts , Fetus , Liver , Megakaryocyte Progenitor Cells , Megakaryocytes , Membranes , Mitochondria , Polyribosomes , ThrombopoiesisABSTRACT
The presence of erythroblasts within Kupffer cell was studied for transmission electron microscopically with 5 human fetal livers from 11 to 23 weeks of gestation during the high activity of hepatic hemopoiesis. By using continuous series of thin sections electron microscopically, the objective of the present study was to evaluate the relevance between a migrated erythroblast and a Kupffer cell, and the migration of erythroblasts within Kupffer cells in the sinusoidal lumen. During the examined period the sinusoidal wall consisted of endothelial cells and Kupffer cells, being deficient in basement membrane. Erythropoietic cell-Kupffer cell interaction was often found as the emperipolesis and adhesion between the cells in human fetal liver under electron microscopy. The cytoplasm of the emperipoletic Kupffer cell contained several mitochondria, rough endoplasmic reticuli, clear vesicles, electron dense bodies, cellular debris with shrunken chromatin of enucleated nuclei, intact enucleated nuclei, and erythroblast bearing vacuoles as intact erythroblasts. Intracellular erythroblasts in the Kupffer cell remain unaltered with their normal structure and showed mitosis, enucleation and migration of erythroblast into the sinusoidal lumen. And a clear zone of a vacuole was readily seen around the intracellular erythroblast within Kupffer cell. On occasion, the hypertropic Kupffer cell with interacellular erythroblasts virtually occluded the sinusoidal lining cell. Processing of a migrating emperipoletic erythroblast within a Kupffer cell, the erythroblast migrated via migration pore through the luminal cell membrane of the Kupffer cell into the sinusoidal lumen. An invasion of a proerythroblast into Kupffer cell or a migration of the cell into the sinusoidal lumen had been found in human fetal liver from 11 to 13 weeks of gestation. The results demonstrate that migration of emperipoletic erythroblasts within Kupffer cells occurs in human hepatic hemopoiesis. We suggest that emperipolsis may be one of the mechanisms that support the maturation of erythroblasts in human fetal liver.