Multicentric reticulohistiocytosis: a rare case report.

A 58-year-old lady presented with polyarthritis followed by multiple shiny erythematous dome-shaped papulonodules mainly over the face, around joints and coral bead sign on fingers without any mucosal involvement. Characteristic histopathology with well-defined dermal infiltrate consisting of multinucleated giant cells and large macrophages having abundant eosinophilic cytoplasm clinched the diagnosis of multicentric reticulohistiocytosis.

Introduction

Multicentric reticulohistiocytosis (MRH) is a rare histiocytic proliferative disease in which joints, skin, mucous membranes and internal organs are affected.[1] The most prominent clinical features are distinctive cutaneous nodules and destructive arthritis.[2] Twenty five percent of the patients have an associated internal malignancy at various sites. MRH has few other names in the literature as lipoid dermatoarthritis, giant cell histiocytoma, reticulohistiocytic granuloma. This is a rare condition, fewer than 200 cases have been reported in the world literature[3] and to the best of our knowledge this is the third case reported from India.

Case Report

A 58-year-old female presented with destructive polyarthritis of small joints of the hands, wrists, elbows and knee joints for past one and half years. She also developed multiple papulonodules on the forearm, elbow [Figure 1], face [Figure 2], ears helices and knee for last 6 months. The papulonodules were mildly erythematous, dome-shaped, glistening, translucent and non-pruritic and non-tender. The sizes varied from small papules to large pea-sized. There was a tendency to grouping of the lesions. Many small papules along the nail folds were seen forming the “coral bead sign” [Figure 3]. The surrounding skin was normal. The oral mucosa was free.

Figure 1

Shows typical erythematous glistening papulonodules around left elbow joint

Figure 2

Typical lesions on central part of the face

Figure 3

The “coral bead sign” on nail folds

An extensive laboratory evaluation including complete hemogram, ESR, lipid profile, chest X-ray, USG abdomen, urinanalysis, stool for occult blood, ANA and X-ray of hand were done. Investigations revealed mild normocytic normochromic anemia (Hb-9.2 g/dl), raised ESR (55mm in 1st hr) and increased triglyceride level (175 mg/dl). USG abdomen showed mild splenomegaly and X-ray of the chest was normal but X-ray of the hand showed erosion in the proximal and distal interphalangeal joints.

Skin punch biopsy was done from a nodule at the elbow region. The histopathological examination revealed well defined dermal infiltrate consisting of multinucleated giant cells and macrophages having abundant eosinophilic finely granular cytoplasm with ground glass appearance [Figure 4]. These features are consistent with MRH.

Figure 4

Histopathology showing multinucleated giant cells and macrophages having abundant eosinophilic finely granular cytoplasm in the dermis (H and E, ×200)

Discussion

MRH is a class II or non-Langerhans cell histiocytosis, characterized by local proliferation of resident mononuclear phagocytes other than Langerhans cell.[4]

The onset of MRH is usually insidious and cutaneous manifestations usually follow the articular signs and symptoms.[4]

The typical cutaneous manifestations consist of nonpruritic, flesh colored to reddish brown yellow papules and nodules that may be found anywhere in the body with a predilection for face, hand and around joints.[5] Around nail folds small papules are found which are called coral beads represent typical clinical sign. Differential diagnosis of the cutaneous lesions includes lepromatous leprosy, sarcoidosis, xanthomatosis, histiocytosis X, juvenile and adult xanthogranuloma, generalized eruptive histiocytoma, familial histiocytic dermatoarthritis and neurofibromatosis. The presence of skin manifestations on the face and hands with erosive arthritis usually differentiates MRH from other diseases.

MRH is associated with multiple medical conditions; underlying malignancy is found in about 25% of the cases.[3] Breast and stomach are the most common sites for underlying malignancy but may occur anywhere. Other conditions include hyperlipidemia, tuberculosis, pregnancy and autoimmune diseases. In our case no underlying malignancy or other disorders could be detected.

In conclusion MRH is a very rare disease; only 200 cases are reported worldwide so far. To the best of our knowledge it is the third case reported from India.