After an oral consent, we present the case of a 58-year-old Tunisian woman, with a history of arterial hypertension and diabetes mellitus who was admitted for weight loss (20 kg), dyspnoea, dry cough and back pain evolving since two years. Physical examination revealed an isolated left subclavicular lymphadenopathy and frontal swelling with no other abnormalities.
Chest radiograph showed bilateral interstitial involvement predominating in the bases (figure 1).
Laboratory investigations showed a normal calcemia, a high level of alkaline phosphatase and gamma glutamyl transferase as well as high level of inflammatory parameters. A computed tomography (CT) scan was realized and showed micronodules with lymphatic distribution in both lungs along with clavicular, mediastinal and abdominal lymph nodes. Liver was dysmorphic and micronodular with perihepatic adenomegaly discretely compressing intrahepatic bile ducts.
Moreover, the computed tomography of the body revealed a multiple mixed, lytic and sclerotic bone lesions with with suspicious signs of malignancy in 7th cervical vertebrae, thoracic vertebrae, 1st and 2nd Sacral vertebra, 6th,9th, tenth right ribs, costal cartilage of the 6th left ribs and a lytic lesion of the frontal bone (figure 2). These findings were suggestive of one of many oncologic processes, with differential diagnoses including metastases or tuberculosis.
These lesions are hypointense on T1 sequence, hypointense surrounded by an hyperintense border on STIR sequence and are mildly enhanced after gadolinium injection (figure 3).
Bone malignancy was the most likely diagnosis.
Flexible bronchoscopy showed inflammatory mucosa and biopsies were negative. Lymphocytosis was found in the bronchoalveolar lavage analysis (lymphocyte count: 46%) with a slight increase in CD4/CD8 ratio (2.4).
Investigations for tuberculosis (Ziehl-Neelsen stain and culture) were negative including tuberculin skin test and mycobacterial stains.
Considering clinical presentation, radiological imaging, biological parameters and histological data the diagnosis of multisystem sarcoidosis was retained.
As the patient presented an altered general state with aggressive osseous lesions in CT, histological confirmation of bone lesions was needed. Costovertebral biopsy dismissed the diagnosis of malignancy and confirmed the granulomatous inflammation without caseous necrosis (figures 4, 5).
The other lesions (lung, lymph nodes skin and liver) were not biopsied.
Finally, the diagnosis of systemic sarcoidosis with bone involvement was confirmed.
At the time of diagnosis, pulmonary function tests showed a forced expiratory volume in 1 s (FEV1): 1.05 L (51% of predicted) and FEV1/forced vital capacity (FVC): 55%. Six-minute walking distance (TM6) was 454m (65% of predicted value) without any impact neither on peripheral oxygen saturation nor on dyspnoea class: 2 (Borg scale).
As the patient was symptomatic (dyspnoea, dry cough, weight loss,) along with abnormal pulmonary function tests, we decided to start oral prednisone 0.5mg/kg/day. After two months an excellent response to treatment was observed. In fact, the frontal swelling disappeared in the 3rd day of treatment and functional explorations showed an improvement of TM6 (79% of predicted value), FEV1 (from 51% to 73%), FVC (from 78% to 80%) and FEV1/FVC (from 55% to 72%).
Glucocorticoid-based treatment was maintained for a total of 18 months without a vitamin D supplementation. The patient was followed for 3 years. Her back pain gradually decreased. There was no progression or involvement of other bones or new skin lesions.