Multicentric reticulohistiocytosis: a report of a case and a review of the pathology

Reticulohistiocytosis

Reticulohistiocytoses consist of a rare group of diseases caused by CD68+ macrophage proliferation. Several advances have been achieved in relation to the receptors involved in these diseases. This knowledge will clarify the physiopathologic mechanisms of the reticulohistiocytoses and direct better therapeutic approaches for patients.

Multicentric reticulohistiocytosis: a proliferation of macrophages with tropism for skin and joints, part II

In this second part of the review of multicentric reticulohistiocytosis, the authors discuss its association with other diseases, in particular, cancer, and laboratory and therapeutic aspects of this incapacitating and disfiguring disease. Histopathologic aspects are characteristic: dense mononuclear infiltrate with typical multinucleated cells that contain periodic acid-Schiff-positive and diastasis-resistant material, conferring a "ground glass" aspect when stained with hematoxylineosin.

Osteoclast differentiation and bone resorption in multicentric reticulohistiocytosis

Multicentric reticulohistiocytosis (MR) is a systemic disease of unknown cause characterized by the presence of a heavy macrophage infiltrate in skin and synovial tissues and the development of an erosive polyarthritis. The synovial fluid in MR is known to contain numerous mononuclear cells. In this study, we have determined whether these cells contribute to joint destruction in MR by differentiating them into osteoclasts. Synovial fluid mononuclear cells were isolated from the knee joint of a 44-year-old male with MR. These cells were cultured with various combinations of macrophage-colony stimulating factor, receptor activator for nuclear factor kappaB ligand (RANKL), tumor necrosis factor alpha, interleukin-1alpha, osteoprotegerin, and zoledronate. Osteoclast differentiation was assessed by expression of tartrate-resistant acid phosphatase, vitronectin receptor, and the extent of lacunar resorption. Most MR synovial fluid mononuclear cells expressed a macrophage phenotype (CD14(+), CD68(+), HLA-DR(+), CD11b(+)). Extensive osteoclast formation and lacunar resorption were noted in macrophage-colony stimulating factor/RANKL-treated cell cultures. MR synovial fluid contained increased tumor necrosis factor alpha and decreased osteoprotegerin compared with osteoarthritis synovial fluid. Lacunar resorption was inhibited in cultures containing zoledronate. Pamidronate treatment of the patient also reduced the number of synovial fluid macrophages and resulted in less osteoclast formation and lacunar resorption. MR synovial fluid contains numerous macrophages that are capable of differentiating into osteoclasts by the RANKL signaling pathway. Inhibitors of osteoclast formation and resorption activity may be of use in preventing the severe joint destruction that commonly occurs in MR.

Immunohistochemical profile of multicentric reticulohistiocytosis

BACKGROUND

There is enough evidence to support the knowledge that multicentric reticulohistiocytosis (MR) is a histiocytic proliferative disorder; however, the type of histiocytes involved is not well established.

OBJECTIVE AND METHODS

To study the nature of cells present in MR lesions by studying the immunohistochemical profile of three new cases and reviewing 23 cases reported in the literature.

RESULTS

MR histiocytic cells are positive for vimentin, CD68, and CD45, negative for S-100 protein, CD34, and XIIIa factor, and weak reactors for thrombomodulin. Small activated histiocytes are MAC387 positive. Lymphocytes, mainly CD4+ cells, are found in MR infiltrates.

CONCLUSIONS

The MR immunophenotypic pattern does not suggest a type I or type II dendrocyte or a Langerhans cell origin. On the other hand, it points to a different cell derived from the monocyte-macrophage line. CD4+ cells may be responsible for activating the proliferation of histiocytic cells. Small histiocytic MAC387+ cells are likely to become the MR multinucleated giant cells.

Multicentric reticulohistiocytosis

BACKGROUND

Multicentric reticulohistiocytosis (MR) is a rare histiocytic systemic disease mainly affecting the skin and synovia.

OBJECTIVE

To present the main and newest aspects of MR.

METHOD

A review of the current medical literature, composing a retrospective study of 96 case reports published world-wide since 1977.

RESULTS

Facial and hand skin nodules with symmetric arthritis were the most frequent clinical presentation. The pathognomonic sign of'coral beads' and vermicular erythematous lesions bordering nostrils, seems to be very characteristic of MR. There is a significant association with cancer. Histiocytic cells of MR are best characterized on immunohistochemistry by its immunoreactivity for vimentin, CD68 and CD45 and non-reactivity for S-100 protein, CD34 and factor XIIIa. Although the outcome of the disease is usually very limiting for the patients, treatment with immunosuppressive drugs may be useful.

CONCLUSION

MR is a unique histiocytic proliferative disease with a peculiar immunophenotypic pattern and distinctive clinical and histopathological aspects.

Malignancy-associated multicentric reticulohistiocytosis: a clinical, histological and immunophenotypic study

The clinical, histopathological, and immunophenotypic characteristics of four cases of malignancy-associated multicentric reticulohistiocytosis (MMR) and one case each of diffuse cutaneous reticulohistiocytosis (DCR) and isolated reticulohistiocytoma (IR), are reviewed. In all four cases of MMR the cutaneous lesions and joint manifestations were judged to be concurrent with the diagnosis of malignancy. Malignancies observed included one case each of pancreatic adenocarcinoma, squamous cell carcinoma of the lung, metastatic melanoma and intraperitoneal grade 4 mucinous adenocarcinoma of uncertain origin. Histologically, all six cases demonstrated the typical changes of a diffuse histiocytic and multinucleated giant cell infiltrate with ground-glass cytoplasm, predominantly in the upper dermis. Immunohistochemical investigation revealed strong cytoplasmic staining with KP-1 (CD68) in all six cases. Prominent membrane staining was noted with leucocyte common antigen (CD45) in four cases (three MMR and one IR), and CD3 in four cases (three MMR and one IR). Weak membrane staining with Leu 22 (CD43) was noted in two MMR cases. UCHL-1 (CD45RO), L26 (CD20), S-100 and BerH2 stains were all uniformly negative. A prominent number of perilesional factor XIIIa-positive dermal dendrocytes were noted in the single case of IR, in contrast with the other five cases. We conclude that MMR, DCR and IR are histopathologically and immunohistochemically similar. The pattern of immunoreactivity observed is consistent with a monocyte-macrophage origin of the infiltrating tumour cells. We emphasize the paraneoplastic association of multicentric reticulohistiocytosis, which we have observed in four of 13 such cases (31%) evaluated at our institution.

Radiologic case study. Multicentric reticulohistiocytosis

MRH is somewhat similar to, and probably occasionally mistaken for, psoriatic arthritis, Reiter's syndrome, or less frequently, rheumatoid arthritis. However, several important features distinguish MRH from the other arthritides. Rheumatoid arthritis more commonly involves the metacarpophalangeal joints, while MRH ordinarily affects the distal interphalangeal and proximal interphalangeal joints. Furthermore, MRH rarely exhibits the degree of articular osteopenia that is the hallmark of rheumatoid disease. While psoriatic arthritis and Reiter's often affect the DIP joints, they rarely display the symmetry of MRH. In addition, MRH does not demonstrate the periosteal new bone formation that is seen in both psoriatic arthritis and Reiter's syndrome. Hence, the diagnosis of MRH may be made with reasonable confidence on the radiologic findings alone, even before the cutaneous nodules appear, which can then be biopsied to confirm the diagnosis.

Multicentric reticulohistiocytosis: systemic macrophage disorder

Multicentric reticulohistiocytosis is a rare multisystem disorder that reflects a reactive inflammatory response to an undetermined stimulus. While the disease is characterized as a dermatoarthritis, multiple organ systems including cardiac and skeletal muscle, the pleura and gastrointestinal tract have been involved in reported cases. The synovitis can be quite destructive with arthritis mutilans developing in a substantial percentage. The dermatitis may be particularly disfiguring when the face is involved. This chapter describes the clinical and laboratory features of the 33 cases of MRH previously reviewed by Barrow and Holubar and an additional 33 cases that have appeared in the medical literature since that report. We note an apparent decline in frequency of some manifestations of MRH. This may be due in part to the nature of the recent reports which often present a brief clinical report and focus primarily on specific disease associations, unusual manifestations, new organ system involvement or treatment regimens. The primary cell involved in the reactive inflammatory response of MRH is the phagocytic tissue histiocyte (macrophage). While uncontrolled proliferation of these reticulohistiocytes is seen in several infectious and malignant conditions there is presently no direct evidence of a particular organism or neoplasm involved in the aetiopathogenesis of MRH. There is evidence of tuberculosis exposure in one third of cases with active tuberculosis present in 5%. Likewise, malignancies are reported concomitantly with MRH in 15-28% of cases. The therapeutic trend in MRH is to treat early and aggressively to prevent the devastating arthropathy and disfiguring cutaneous sequelae. This recommendation, however, is largely based on anecdotal reports and thus the physician encountering a case of MRH needs to proceed with circumspection.