Osseous Sarcoid-like Reaction in Sigmoid Colon Cancer Requiring Differentiation from Bone Metastasis

Area of Science:

• Oncology
• Pathology

Background:

• Sarcoid-like reactions are rare but can be associated with various cancers, including colorectal cancer.
• Osseous sarcoid-like reactions can mimic metastatic disease, posing diagnostic challenges.

Purpose of the Study:

• To report a case of sigmoid adenocarcinoma with coexisting osseous sarcoid-like reactions.
• To highlight the importance of considering sarcoid-like reactions in the differential diagnosis of bone lesions in colorectal cancer patients.

Main Methods:

• Case report of a 50-year-old woman with sigmoid adenocarcinoma.
• Utilized positron emission tomography-computed tomography (PET-CT) for imaging.
• Performed bone and lymph node biopsies for histopathological examination.

Main Results:

• PET-CT showed uptake in the iliac bone and para-aortic lymph nodes, initially suspicious for metastases.
• Biopsies revealed epithelioid non-caseating granulomas, characteristic of sarcoid-like reactions, not metastatic cancer.
• Final diagnosis was pathological T2N2aM0, Stage IIIB colorectal cancer with associated sarcoid-like reactions.

Conclusions:

• Sarcoid-like reactions can present as bone lesions in colorectal cancer patients, mimicking metastases.
• When bone lesions show an atypical depth of invasion for metastases, sarcoid-like reactions should be considered.
• Histopathological evaluation is essential for accurate diagnosis and appropriate patient management.