Morpheaform sarcoidosis: A case presentation of an uncommon cutaneous manifestation of sarcoidosis.

Introduction

Sarcoidosis is a systemic granulomatous disorder of unknown etiology that can virtually involve any organ system. The most commonly affected sites include lungs, thoracic lymph nodes, eyes, heart, and central nervous system, with skin involvement in an estimated 20% to 35% of patients.,

The cutaneous manifestations of sarcoidosis are heterogeneous; however, these are broadly classified as “specific” if they contain noncaseating granulomas on histopathologic examination or as “nonspecific” if they lack this hallmark feature (Table I)., Morpheaform sarcoidosis is a “specific” variant that can represent a particular diagnostic challenge. Due to its clinical resemblance to morphea, patients are often misdiagnosed as having localized scleroderma. Here, we describe a patient who was thought to have morphea but later diagnosed with skin-limited morpheaform sarcoidosis.

Table I

Examples of specific and nonspecific lesions of cutaneous sarcoidosis

Specific lesions	Nonspecific lesions
Lupus pernio	Erythema nodosum
Macules	Clubbing
Papules	Calcinosis cutis
Plaques	Nummular eczema
Infiltrative scars	Erythema multiforme
Subcutaneous nodules of Darier-Roussy
Psoriasiform
Erythrodermic
Ichthyosiform
Angiolupoid
Verrucous
Ulcerative
Atrophic
Morpheaform

Case report

A 58-year-old African American woman with no remarkable past medical history, including no history of diabetes or peripheral vascular disease, was referred by her dermatologist to the scleroderma clinic in our rheumatology division for consideration of localized scleroderma (morphea). She had a large plaque on the lower portion of her right leg, which had been worsening over several years. Her dermatologist had biopsied the lesion, and the pathology was consistent with scleroderma. Upon presentation to our clinic, she reported darkened “tight” skin as well as muscle and bone pain deep to the area of skin changes. Physical examination demonstrated a tightly adherent, thickened, and hyperpigmented plaque over the anterior aspect of the right shin (Fig 1). Laboratory findings were unremarkable, including a normal complete blood cell count with differential, comprehensive metabolic panel, erythrocyte sedimentation rate, and C-reactive protein. Her purified protein derivative was negative and pulmonary function tests demonstrated only a mild obstruction. Radiograph and computed tomography scan of the chest were normal, and she had no other evidence of systemic disease. Radiographs of the right leg were unremarkable. Due to muscle and bone pain deep to the cutaneous lesion, a magnetic resonance imaging of the right leg was performed, and it revealed an extensive, diffuse T2 signal hyperintensity that involved the superficial and deep musculature and adipose layer concerning for inflammatory myositis or eosinophilic fasciitis (Fig 2). A full-thickness biopsy, including the fascia, was performed, and it demonstrated an extensive granulomatous infiltrate extending throughout the subcutaneous tissue. No central necrosis or caseation was seen, and the granulomas were devoid of peripheral lymphocytes. Polarized light examination and special infectious stains were negative. Together, these changes were compatible with a diagnosis of sarcoidosis and were not consistent with eosinophilic fasciitis, necrobiosis lipoidica, lipodermatosclerosis, or morphea. A diagnosis of morpheaform sarcoidosis was thus confirmed on the basis of clinical and histopathologic findings. She was treated with tapering oral prednisone, hydroxychloroquine, and methotrexate and experienced improvement in her skin lesion and resolution of her muscle and bone pain. She has been followed for 8 years since her diagnosis, and the condition remains well controlled with hydroxychloroquine and methotrexate with no evidence of systemic sarcoidosis.

Fig 1

Hyperpigmented, thickened, and sclerotic plaque over the right shin.

Fig 2

Magnetic resonance imaging scan demonstrated diffuse T2 signal hyperintensity within the superficial and deep musculature and adipose tissue.

Discussion

Morpheaform sarcoidosis is a rare presentation of cutaneous sarcoidosis. Including our patient, only 9 cases have been reported in the literature.3, 4, 5, 6, 7, 8 Of the 9 patients, the majority (7 of 9) are women. Five cases occurred in White patients and 4 in Black patients. The median age (interquartile range) at the time of diagnosis was 58 years (41-71 years).3, 4, 5, 6, 7, 8 Although most of the cases occurred later in life, 1 was reported in a 17-year-old patient. The morpheaform eruption was the initial manifestation of sarcoidosis in 7 patients and occurred years after the diagnosis of systemic sarcoidosis in 2 patients. The distribution and number of lesions were also heterogeneous.3, 4, 5, 6, 7, 8 Two had a linear eruption, resembling linear morphea., Cases of both skin-limited morpheaform sarcoidosis and morpheaform lesions in the context of systemic sarcoidosis have been reported.3, 4, 5, 6, 7, 8

Our patient presented with skin-limited morpheaform sarcoidosis. For patients with skin-limited disease, the risk for the development of systemic involvement is unknown. It is thought that 30% to 85% of the patients with cutaneous disease will develop systemic manifestations., Although the majority of patients who present with cutaneous disease are found to have systemic involvement at the time of diagnosis, skin lesions can present years prior to additional organ involvement., Because of this, continued surveillance is recommended., Our patient has had no evidence of systemic involvement over 8 years of follow-up.

Numerous studies have demonstrated that systemic involvement and disease prognosis can be predicted by the lesion's morphology., Plaque type and lupus pernio are associated with a worse prognosis as they are more likely to have severe and persistent pulmonary and extrathoracic involvement., Erythema nodosum, often associated with Lofgren syndrome, and macular and papular eruptions are associated with an overall benign course., The relationship between morpheaform sarcoidosis and disease prognosis is unknown., Of the 9 cases published, 3 patients reported symptoms consistent with chronic sarcoid arthritis., Although the sample size is too small to postulate a clinical correlation between morpheaform sarcoidosis and chronic sarcoid arthritis, this may be of interest for further studies.

The patient in the case we presented had no pulmonary symptoms and a normal radiograph and computed tomography scan of the chest. Although pulmonary function tests showed a mild obstruction, this test cannot reliably be used in isolation to diagnose pulmonary involvement., Our patient also presented with muscle and bone pain deep to the cutaneous lesion. She had no evidence of sarcoidal bone involvement, and her presentation was not consistent with any of the 3 well-defined variants of sarcoid myopathy. We, therefore, postulate that the patient's pain and increased T2 signal were most likely due to a reactive inflammatory process secondary to the extensive granulomatous infiltrate.

Treatment for cutaneous sarcoidosis is based on limited data. The current widely accepted therapies include corticosteroids, antimalarials, and methotrexate., Several cases support the effectiveness of hydroxychloroquine in treating morpheaform sarcoidosis.3, 4, 5, 6, 7, 8 In addition to hydroxychloroquine, our patient is maintained on methotrexate and has had continued resolution of symptoms.

In conclusion, morpheaform sarcoidosis is an important differential diagnosis for clinicians to consider in a patient being evaluated for localized scleroderma. Knowledge of the various forms of cutaneous sarcoidosis can aid in the evaluation of patients who present with unusual skin lesions to rheumatology and dermatology clinics.

Conflicts of interest

None disclosed.