PO39 - Sarcoidosis Mimicking Malignancy: A Diagnostic Challenge
Inês de Brito Gonçalves (Portugal)1; Carla Margarida Carvalho (Portugal)1; Raquel Pereira (Portugal)1; Eva Dias Padrão (Portugal);
1 - Unidade Local de Saúde de Braga;
Keywords: Sarcoidosis; Multisystem involvement; Malignancy mimicry;
Select the theme: Challenges in Sarcoidosis Diagnosis and Staging
Type: Clinical Cases
Presentation: Poster Presentation

Introduction:

Sarcoidosis is a systemic granulomatous disease with variable clinical presentation. While thoracic involvement predominates, extensive multisystemic disease with hypermetabolic lesions on positron emission tomography (PET) may mimic lymphoproliferative or metastatic malignancy, posing a diagnostic challenge.

Clinical Case Description:

A 75-year-old woman, never-smoker, with a history of asthma and no relevant occupational or environmental exposures, was investigated for asthenia, anorexia and significant weight loss. Thoracoabdominal CT in January 2025 showed multiple thoracic and extrathoracic adenopathies (mediastinal, hilar, supraclavicular, axillary, abdominal/mesenteric, iliac and inguinal), bilateral pulmonary micronodules with a perilymphatic distribution and right perihilar mass-like opacities, as well as splenic nodules. PET scan demonstrated diffuse supra- and infradiaphragmatic hypermetabolic adenopathy, pulmonary nodules, intense splenic uptake, and hypermetabolic soft-tissue lesions, raising strong suspicion of lymphoproliferative malignancy.

Bronchoscopic evaluation with EBUS-guided sampling of station 4L identified non-necrotising epithelioid granulomas, while bronchoalveolar samples were negative for malignancy and infection. Excisional biopsy of a right inguinal lymph node confirmed sarcoid-type granulomatous inflammation, with multinucleated giant cells, including Langhans-type forms. Histochemical stains for microorganisms were negative. Laboratory work-up showed elevated angiotensin-converting enzyme (ACE) levels, hypercalcaemia with suppressed parathyroid hormone, mild renal dysfunction, elevated inflammatory markers, and negative ANA/ANCA.

The overall clinicoradiological and histological findings supported diagnosis of stage II thoracic sarcoidosis with significant extrathoracic involvement, associated with hypercalcaemia and renal impairment. Oral prednisolone was initiated in May 2025 and subsequently tapered, leading to improvement in calcium levels and renal function, normalisation of ACE and inflammatory markers, along with clinical stability.

Conclusions:

This case illustrates multisystem sarcoidosis mimicking disseminated lymphoproliferative malignancy on CT and PET. It highlights the importance of tissue biopsy for diagnosis and exclusion of malignancy or infection, with clinical and analytical response to corticosteroids supporting diagnosis. Sarcoidosis should be considered in patients with diffuse adenopathy, pulmonary nodules, splenic lesions and hypercalcaemia, even when imaging is highly suggestive of malignancy.