[Should we look for neoplasia in a patient with unexplained granulomatosis?]

[Metastasis or sarcoidosis - a diagnostic pitfall in metastatic rectal carcinoma]

BACKGROUND

Granulomatous diseases as sarcoidosis can impair the staging of metastatic diseases since metastasis are hard to distinguish from granulomas in standard imaging. This case report describes the diagnostic workup and therapy in a patient with simultaneous sarcoidosis and rectal cancer with hepatic metastasis and how a curative stadium was achieved.

CASE DESCRIPTION

A 71-year old male patient was diagnosed with an adenocarcinoma of the rectum after presenting with involuntary weight loss and anemia. Further diagnostics raised strong suspicion of hepatic, pulmonary and splenic metastasis. Histology after bronchoscopy surprisingly discovered non-caseating granulomas, leading to the diagnosis of sarcoidosis. Due to an obstructive tumor, a rectum resection was performed. Due to a high suspicion of splenic metastasis during surgery, the spleen was removed. Histology revealed no metastasis in the spleen but multiple granulomas due to sarcoidosis. After surgery, biopsy of a suspicious lesion in the liver revealed both metastasis and sarcoidosis in the same sample. The patient was treated with a pseudo(neo)adjuvant chemotherapy with 5-Fluorouracil, Leukovorin, Oxaliplatin (FOLFOX) and Panitumumab (Anti-EGF-antibody). After treatment, CT scan revealed two hepatic lesions decreasing in size, while all other lesions were metrically stable. A right hemihepatectomy followed and histology revealed both sarcoidosis and metastasis. The curated patient was sent to aftercare and there is no suspicion for a relapse (13 month after last surgery).

DISCUSSION

The simultaneous appearance of metastatic tumors and sarcoidosis creates a diagnostic dilemma since both manifestations can barely be distinguished in regular imaging technologies. This case report demonstrates that the histological work-up of affected organs with consecutive resections can cure a patient of a metastatic tumor disease, even in the context of simultaneous sarcoidosis.

Sarcoidosis and Cancer: A Complex Relationship

Sarcoidosis is a systemic disease of unknown etiology, characterized by the presence of non-caseating granulomas in various organs, mainly the lungs, and the lymphatic system. Since the individualization of sarcoidosis-lymphoma association by Brincker et al., the relationship between sarcoidosis or granulomatous syndromes and malignancies has been clarified through observational studies worldwide. Two recent meta-analyses showed an increased risk of neoplasia in sarcoidosis. The granulomatosis can also reveal malignancy, either solid or hematological, defining paraneoplastic sarcoidosis. Recent cancer immunotherapies, including immune checkpoint inhibitors (targeting PD-1, PD-L1, or CTLA-4) and BRAF or MEK inhibitors were also reported as possible inducers of sarcoidosis-like reactions. Sarcoidosis and neoplasia, especially lymphoma, can show overlapping presentations, thus making the diagnosis and treatment harder to deal with. There are currently no formal recommendations to guide the differential diagnosis workup between the evolution of lymphoma or a solid cancer and a granulomatous reaction associated with neoplasia. Thus, in atypical presentations (e.g., deeply impaired condition, compressive lymphadenopathy, atypical localization, unexplained worsening lymphadenopathy, or splenomegaly), and treatment-resistant disease, targeted biopsies on suspect localizations with histological examination could help the clinician to differentiate neoplasia from sarcoidosis. Pathological diagnosis could sometimes be challenging since very few tumor cells may be surrounded by massive granulomatous reaction. The sensitization of currently available diagnostic tools should improve the diagnostic accuracy, such as the use of more “cancer-specific” radioactive tracers coupled with Positron Emission Tomography scan.

Refractory Sarcoidosis: A Review

Sarcoidosis is a multi-system disease of unknown etiology characterized by granuloma formation in various organs (especially lung and mediastinohilar lymph nodes). In more than half of patients, the disease resolves spontaneously. When indicated, it usually responds to corticosteroids, the first-line treatment, but some patients may not respond or tolerate them. An absence of treatment response is rare and urges for verifying the absence of a diagnosis error, the good adherence of the treatment, the presence of active lesions susceptible to respond since fibrotic lesions are irreversible. That is when second-line treatments, immunosuppressants (methotrexate, leflunomide, azathioprine, mycophenolate mofetil, hydroxychloroquine), should be considered. Methotrexate is the only first-line immunosuppressant validated by a randomized controlled trial. Refractory sarcoidosis is not yet a well-defined condition, but it remains a real challenge for the physicians. Herein, we considered refractory sarcoidosis as a disease in which second-line treatments are not sufficient to achieve satisfying disease control or satisfying corticosteroids tapering. Tumor necrosis alpha inhibitors, third-line treatments, have been validated through randomized controlled trials. There are currently no guidelines or recommendations regarding refractory sarcoidosis. Moreover, criteria defining non-response to treatment need to be clearly specified. The delay to achieve response to organ involvement and drugs also should be defined. In the past ten years, the efficacy of several immunosuppressants beforehand used in other autoimmune or inflammatory diseases was reported in refractory cases series. Among them, anti-CD20 antibodies (rituximab), repository corticotrophin injection, and anti-JAK therapy anti-interleukin-6 receptor monoclonal antibody (tocilizumab) were the main reported. Unfortunately, no clinical trial is available to validate their use in the case of sarcoidosis. Currently, other immunosuppressants such as JAK inhibitors are on trial to assess their efficacy in sarcoidosis. In this review, we propose to summarize the state of the art regarding the use of immunosuppressants and their management in the case of refractory or multidrug-resistant sarcoidosis.