Multiple cutaneous reticulohistiocytoma in middle aged female.

Multiple cutaneous reticulohistiocytoma (MCR) and multicentric reticulohistiocytosis (MR) are rare, idiopathic histiocytic granulomatous disorders presenting in a spectrum. A 35-year-old female presented with multiple, firm, discrete, asymptomatic nodules, 1-2 cm in size over face, back, abdomen, thighs, and legs. There were no systemic symptoms. Histopathology of a nodule over trunk showed diffuse, dense infiltrate of large histiocytes, and histiocytic giant cells. The histiocytes had rounded vesicular nuclei and abundant pink homogenously stained ground glass cytoplasm. The diagnosis of MCR was made. Systemic evaluation did not reveal any abnormality. Considering the cosmetic appearance of facial lesions, patient was referred to the plastic surgeon. No treatment was advised for rest of lesions and patient was asked to review every 6 months or if any new complaints develop.

INTRODUCTION

Reticulohistiocytosis is a spectrum of disorders ranging from solitary and diffuse cutaneous forms without systemic involvement to multicentric reticulohistiocytosis (MR).[1] The primary skin lesion, reticulohistiocytoma, usually presents as a firm, skin colored, yellowish or reddish papule or nodule.[2] In multiple cutaneous reticulohistiocytoma (MCR), there is onset of multiple lesions without underlying systemic illness, whereas in MR there are extensive skin lesions in association with a severe, often destructive arthropathy, and systemic features.[3]

MCR is more common in young adult males and MR in middle aged women associated with systemic symptoms. Both the variants are characterized in histo-pathology by the presence of large mononucleated or multinucleated histiocytes with an abundance of eosinophilic, homogenous to finely granular cytoplasm having a ground glass appearance.[45] We report here a case of MCR in a middle aged female for its rarity and the importance of ruling out MR in such a patient.

CASE REPORT

A 35-year-old female presented with gradual onset of multiple skin colored, asymptomatic pea sized swellings, which started with face and gradually involved back, arms, and legs. There was no history of preceding local trauma, discharge, pain in these lesions. There were no constitutional symptoms like fever, joint pain, and complaints referable to other systems. The patient's main concern was regarding the cosmetic appearance as lesions were present over the face. Her family history was negative and she had no history of any other chronic illness.

The patient appeared in good general health with normal weight and height. Mucocutaneous examination revealed multiple (20 in number), discrete, skin colored nodules, 1–2 cm in size scattered over her face, back, abdomen, thighs, and lower legs [Figure 1]. They were firm in consistency, non tender with a smooth surface. Hair, nail, and mucosa were normal. Her systemic examination did not reveal any abnormality. Her complete blood count along with general blood picture, liver, and renal function tests, fasting lipid profile and urinalysis were normal. Abdominal and pelvis ultrasound were found to be normal. Radiographs of chest, knee, and bilateral hands were found to be normal. Rheumatoid factor and antinuclear antibodies were found to be within normal limits. On the basis of history and clinical examination, differential diagnosis of xanthoma, reticulohistiocytoma, sarcoidosis, and histoid leprosy were made.

Figure 1

(a) Multiple discrete skin colored nodular lesions over back (arrow) (b) Discrete skin colored nodular lesions over face, (c) Discrete skin colored nodular lesions over back, (d) Discrete skin colored nodular lesions over posterior aspect of left thigh and leg

Excisional biopsy of a nodule over the trunk was done and histopathological examination revealed circumscribed large focus of diffuse dense infiltrate of large histiocytes and histiocytic giant cells with scattering of lymphocytes and a few neutrophils [Figure 2]. The histiocytes had rounded vesicular nuclei and abundant pink homogenous stained ground glass cytoplasm. Some of these also had foamy cytoplasm. Several histiocytic giant cells resembling the Touton giant cells were also seen [Figure 3]. Overlying epidermis showed flattening and thinning and was covered by parakeratosis containing collection of neutrophils. Based on clinical and histopathological findings a diagnosis of multiple cutaneous reticulohistocytoma was made. The nature of the disease was explained to the patient and was referred to the plastic surgeon for the cosmetic correction of the facial lesion. Patient was advised to review if any new lesions or any new complaints develop. Lesions remained stable with no significant disability even after 6 months of follow up.

Figure 2

Skin biopsy showing lymphocytic infiltrate with histiocytes and giant cells [H and E, ×100]

Figure 3

Skin biopsy showing multinucleated giant cells (arrow) with an amorphous eosinophilic cytoplasm [H and E, ×400]

DISCUSSION

Non-langerhans cells histiocytosis represents a broad group of different disorders characterized commonly by proliferation of histiocytes other than langerhans cells. MCR represents a unique pattern in the spectrum of the reticulohistiocytoses, characterized by histiocytic proliferations of the skin and soft tissues.[1] The pathogenesis of the disease is unknown. It may represent an abnormality histiocytic reaction to different stimuli. Local trauma may play a role in the pathogenesis of solitary cutaneous histiocytoma, whereas in diffuse forms, the association with internal malignancies and autoimmune diseases suggest an immunologic basis. Reticulohistiocytomas are usually solitary lesions of less than 1 cm in diameter. However, multiple lesions and large reticulocytomas have been rarely reported.[2] Histopathology of reticulohistiocytoma often shows mid-dermal infiltration of mononuclear histiocytes and multinucleated histiocytes with a ground-glass appearance and a variable number of vacuolated, spindle shaped, and xanthomatized mononuclear histiocytes.[456] Immunohistochemical profiles show positivity with different macrophage markers including lysozyme, and alpha 1-antitrypsin. Vimentin is universally positive but all other markers like S-100, desmin, and smooth muscle-specific actin remain negative.[46] Histology along with immunology helps in confirming the diagnosis. There is no specific treatment mentioned for the cutaneous histiocytoma. Pulsed dye laser, oral corticosteroids, and methotrexate has been tried in the treatment of extensive lesions.[78] The only concern in our patient was regarding the physical appearance of the lesions as they were also present over the face. However, patient of MCR needs to be followed up regularly for long time to look for the development of MR which has various life threatening systemic complications. This case thus lays emphasis on considering MCR in the differential diagnosis of asymptomatic skin colored papulo-nodular lesions and adequate systemic evaluation and follow up of such patients.