|Ahead of print publication
Extrapulmonary sarcoidosis presenting as myositis: A rare case
Niraj Bohania, Sumeet Singla, Jagriti Nahata, Pijush Kanti Nandi, Seema Daksh, S Anuradha
Department of Medicine, Maulana Azad Medical College, New Delhi, India
Department of Medicine, Maulana Azad Medical College, Room No 117, B. L Taneja Building, Bahadur Shah Zafar Marg, New Delhi - 110 002
Source of Support: None, Conflict of Interest: None
Sarcoidosis is a multisystem disease with dominant pulmonary involvement (90%). Isolated extrapulmonary involvement is less common. Skeletal muscle (1-2%) involvement is even rare. We report a 40 year old lady presented with easy fatigability, low grade fever for 5-6 months and generalized myalgias. Examination revealed pallor, a receding hair line, hepatomegaly and proximal muscle weakness. Investigations revealed anemia, hypercalcemia and raised serum ACE level. During hospital stay patient developed right sided hemiparesis (acute vasculitic infarct in left parietal cortex). A FDG-PET scan was done which revealed that the muscles of upper and lower limbs showed diffuse, heterogenous areas of increased FDG avidity suggestive of myositis. Final diagnosis of extrapulmonary sarcoidosis (presenting as myositis along with CNS vasculitis and hypercalcemia) was made. Patient showed marked improvement in her symptoms with immunosuppressive therapy. This case is a rare manifestation of extrapulmonary sarcoidosis and emphasizes the role of FDG-PET in diagnosing these cases.
Keywords: Extrapulmonary sarcoidosis, myositis, central nervous system vasculitis, fluorodeoxyglucose positron emission tomography
| Background|| |
Sarcoidosis is a multisystem disease with dominant pulmonary involvement in the form of mediastinal lymphadenopathy and pulmonary infiltrates. Extrapulmonary involvement occurs as ocular (10%–30%), liver (20%–30%) and cutaneous (15%) manifestations. Isolated skeletal muscle involvement is very rare (1%–2%). We report a 40-year-old female who presented with extrapulmonary sarcoidosis with diffuse skeletal muscle involvement. There was no evidence of pulmonary or any other organ involvement.
| Case Report|| |
A 40-year-old female presented with low-grade fever and easy fatigability for 5–6 months. She complained of generalized myalgias, progressive difficulty in getting up from the sitting position, and inability to lift her upper limbs above the shoulders. There was no sensory loss, seizures, and altered consciousness. There was no cough, dyspnea, chest pain, uveitis, or rash. Examination revealed pallor, a receding hair line and hepatomegaly (liver span 17 cm). Neurological examination revealed power of 3/5 in proximal muscle groups and 4+/5 in distal muscle groups in all four limbs. There was severe muscle tenderness in bilateral thighs and arms. The rest of the motor system examination was normal. The higher mental functions, cranial nerves, and sensory examination were unremarkable. Laboratory investigations revealed anemia, hypercalcemia, raised alkaline phosphatase, and raised serum angiotensin converting enzyme (ACE) level [Table 1].
The patient was given intravenous fluids and diuretics along with calcitonin to treat hypercalcemia. Hypercalcemia got corrected over next 3 days. On the 6th day of hospital stay, the patient developed a single episode of generalised tonic clonic seizures (GTCS) and right-sided hemiparesis. The magnetic resonance imaging (MRI) brain (+ MR angiography and venography) revealed an acute infarct in left parietal cortex with occlusion of M1 and M2 segments of left middle cerebral artery (MCA) and attenuated proximal basilar artery likely due to vasculitis [Figure 1]. The patient's hemiparesis improved over a week with conservative management (antiplatelet, statin, and physiotherapy) and calcium level remained normal. However, proximal muscle weakness, muscle pain, and tenderness persisted. Suspecting inflammatory myositis and to look for other organ involvement appropriate for biopsy site, a fluorodeoxyglucose positron emission tomography (FDG-PET) scan was done, which revealed that the muscles of upper and lower limbs showed diffuse, heterogeneous areas of increased FDG avidity suggestive of myositis [Figure 2]. A localized coarse area of calcification along subcutaneous planes of lower back, perineum, and medial thigh were also seen on PET as well as computed tomography scan [Figure 3]. FDG-PET was preferred over MRI as we also wanted to look for another organ involvement (as creatine phosphokinase [CPK] was normal) so that biopsy could have been done from appropriate organ.
|Figure 1: Magnetic resonance angiography showing occlusion of M1 and M2 segments of left MCA and attenuated proximal basilar artery|
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|Figure 2: Fluorodeoxyglucose positron emission tomography computed tomography showing diffuse avidity of uptake in all skeletal muscles|
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|Figure 3: Black arrow showing localized area of subcutaneous calcification|
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Subsequently, a muscle biopsy was taken from right vastus lateralis (showing avidity on FDG-PET scan). It revealed multiple intramysial and subfascial noncaseating granulomas with reticulin stain positive. Biopsy was negative for acid fast bacilli (AFB) [Figure 4].
|Figure 4: Muscle biopsy (×10 and × 20 images): Black arrow showing noncaseating granuloma|
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A final diagnosis of extrapulmonary sarcoidosis (presenting as myositis along with central nervous system [CNS] vasculitis and hypercalcemia) was made. The patient was given pulse steroid therapy for 5 days followed by oral steroid along with injection cyclophosphamide once a month (for 6 months). The patient showed remarkable improvement in her symptoms after initiation of this treatment. There were no further episodes of hypercalcemia and seizures. Muscle weakness improved (proximal muscle power 4+/5 and distal muscle power 5/5) with resolution of muscle pain and tenderness.
| Discussion|| |
Sarcoidosis is a multisystem granulomatous disorder. Pulmonary involvement is most common (>90%), but now more and more cases of extrapulmonary sarcoidosis are being diagnosed due to increased awareness and access to newer investigative modalities. In the present case, a diagnosis of extrapulmonary sarcoidosis was made with the help of FDG-PET scan findings followed by a confirmatory muscle biopsy. FDG-PET and MRI are now recommended as investigations of choice to diagnose muscle sarcoidosis followed by confirmation with muscle biopsy. There are isolated cases that have been diagnosed as muscle sarcoidosis using FDG PET.,,, The MRI is more easily available and less expensive compared to the FDG PET. FDG-PET was preferred over MRI in our case as we also wanted to look for other organ involvement (as repeated CPK was normal) so that biopsy could have been done from appropriate organ. It is well established that CPK levels may be normal in patients with inflammatory myositis. CPK levels may be minimally elevated or even normal in inclusion body myositis, myositis associated with neoplasia, and early presentations of polymyositis and dermatomyositis and when significant muscle atrophy has developed. In a study, 10% of biopsy-confirmed inflammatory myositis had normal CPK levels. Hence, the finding of normal CPK levels in our patient is plausible.
FDG PET also helps in monitoring disease activity and treatment response and predicting relapses in a case of muscle sarcoid.
Extrapulmonary involvement in sarcoidosis is seen in joints, skin, lymph nodes, liver, and spleen. CNS involvement is seen in about 5% of cases usually manifesting as headache, cognitive dysfunction, cranial nerve palsy (most commonly 7th), spinal cord involvement, and meningeal disease. Sarcoidosis presenting as CNS vasculitis is rare. Skeletal muscle involvement is also seen in 1%–2% of cases only and isolated skeletal muscle involvement without pulmonary involvement is extremely rare. Our patient had skeletal muscle involvement with histological evidence of granulomatous inflammation and hypercalcemia, which fulfilled the criteria for extrapulmonary sarcoidosis according to World Association of Sarcoidosis and Other Granulomatous Disorder instrument. Further, the patient made a remarkable recovery with steroids and immunosuppressive treatment.
This case report highlights a rare manifestation of extrapulmonary sarcoidosis, i.e. myositis and emphasizes the role of FDG-PET in diagnosing these cases.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]