About 20℅ of the patients already have metastasis at the time of diagnosis [1]. Liver is the most frequent metastatic site of colorectal carcinoma [3]. An adrenal metastasis from CRC is not uncommon and its prevalence is between 1.9 and 17.4℅ in the autopsy findings [7].
Murakami et al. stated that the resection of the solitary adrenal metastasis is for the benefit of the patient [10]. 5-year survival rate of 37 patients who had gone through adrenalectomy for metastatic disease was analyzed and Kim et al. mentioned that the rate was 24℅ (median 21 month) [6]. As for our patient, an adrenalectomy operation was planned after PET/CT, CT and MRI evaluations pointed right adrenal gland metastasis.
According to Yu-Yi Liu et al. it is necessary to test the serum CEA blood levels for pre-notification of adrenal metastasis during the post-op life of the patient [11] yet there are situations where serum CEA does not indicate the existence of widespread disease, particularly when blood count is normal at the beginning [8]. As for our case, our patient’s serum CEA was examined regularly after the operation. The serum CEA started to increase approximately 4-5 months after the anterior resection, which was compatible with the imaging evaluations.
C. Franzese et al. reported that adrenal gland metastasis responds well to the usage of stereotactic radiotherapy as an ablative treatment [12]. Our patient received right adrenal gland lesion radiotherapy, after the PET/ and CT evaluations, which lasted for 11 days. The lesion showed decrease in size in the CT, which was done 1 month after the RT.
Tsujimoto et al. stated that malign and benign adrenal metastasis can be separated from each other with PET/CT with a sensitivity of 93-100%, specificity of 80-100℅ and accuracy of 92 to 100℅ [6]. Our patient’s PET/CT showed uptake in F-FDG in the right adrenal gland and was compatible with right adrenal gland metastatic lesion suspicion. However, the microscopic examination showed mix inflammatory cells and histiocytes with hemorrhage and necrosis. Castaldi et al. mentioned that PET/CT is inconsistent, and the literature does not contain profound analysis regarding PET/CT [13].
As for CT according to Castaldi et al. a combination of delay enhanced and unenhanced CT can properly classify adrenal masses with a sensitivity of 96-98℅, accuracy of 81-96℅ and specificity of 61-92℅ [13]. However, Yu-Yi Liu stated that CT cannot differentiate between primary lesions, secondary lesions and incidentalomas successfully [11]. In our case two enhanced CTs were done (one after RT) and the two of them identified metastatic lesions with different dimensions.
Katayama et al. described a potential route for hematogenous spread from the original location by which of lungs to the adrenal glands [11]. It is indeed uncommon for colorectal cancer to spread to the adrenal glands skipping the lungs and liver. In the guidelines, made for adrenal incidentalomas, it is not indicated to perform biopsy if the imaging evaluations are compatible with the diagnosis. Leyendecker et al. stated that if an adrenal mass is still suspicious after imaging evaluations in a patient with cancer history, an adrenal biopsy is indicated to perform if the presence of metastasis would change the treatment [14]. Adrenal biopsy has an accuracy rate of around 90℅ and a complication rate of 2.8-4.3℅ [15]. However, the type of biopsied mass, knowledge of the radiologists and biopsy technique can alter the diagnostic value of fine-needle aspiration (FNA) biopsy, it can be non-diagnostic with a rate of 0-28℅ of the cases according to above mentioned criteria [15].
There is also the possibility that the reason we could not find any metastatic tissue in the microscopic examination might be the effects of radiotherapy on the cancer cells. Crook et al. mentioned that histologic resolution may take 2-3 years due to the fact of long tumor doubling times and post-mitotic cell death effect of radiotherapy [16]. This article is about prostate cancer, but we can’t disregard this theory while in our case all of the pre-op examinations were for the benefit of adrenal gland metastasis.
These studies and results bring the questions “should biopsy be indicated for situations that is uncommon as solitary adrenal metastases from colorectal carcinoma and how should we manage the situation if the biopsy result was negative (especially after RT)”