# ACR Incidental Adrenal — ACR incidental adrenal mass management

> Management pathway for incidentally detected adrenal masses based on imaging features and size.

**Situação:** vigente · **Órgão:** Adrenal · **Órgão emissor:** American College of Radiology · **Versão:** 2017 · **Ano:** 2017

## Procedência e vigência
- Família: achado incidental
- Tipo de lógica: flat
- Modalidade: CT, MRI
- Fonte primária: Mayo-Smith WW, Song JH, Boland GL, et al.. Management of Incidental Adrenal Masses: A White Paper of the ACR Incidental Findings Committee (2017) — https://doi.org/10.1016/j.jacr.2017.05.001
- Última verificação: 2026-07-24
- Última checagem: 2026-07-24

## Lógica de decisão
Apply the benign-feature and cancer-history precedence before size. Return the exact source branch and required safety caveats; the 2017 algorithm is guidance, not an autonomous diagnosis or treatment order.

## Categorias

| Código | Rótulo | Critérios | Conduta | Risco | Localizador | Verificado |
| --- | --- | --- | --- | --- | --- | --- |
| benign-features | Benign imaging features | Adult incidental asymptomatic adrenal mass with a diagnostic benign feature: unenhanced CT attenuation <=10 HU; signal loss relative to spleen from in-phase to opposed-phase chemical-shift MRI; no enhancement (<10 HU change between precontrast and postcontrast images), consistent with cyst or hemorrhage; or benign calcification. Macroscopic fat is represented by the more specific macroscopic-fat branch. | No additional imaging workup or follow-up is needed once a diagnostic benign feature is established, regardless of size. Imaging cannot establish functional status, so the paper separately advises considering biochemical evaluation for most incidental adrenal masses when clinically relevant. | The 2017 algorithm treats these imaging findings as benign leave-alone endpoints. This classification does not exclude hormonal activity and does not publish a branch-specific numeric probability of malignancy. | Mayo-Smith et al., JACR 2017, Fig. 1 and p.4 'Masses With Diagnostic Benign Imaging Features'; p.5 defines no enhancement as <10 HU change; pp.6-7 discuss functional assessment. | ✓ |
| indeterminate | Indeterminate mass | Adrenal mass >=1 cm without a diagnostic benign feature after applying prior-imaging, cancer-history and size precedence. Examples include attenuation >10 HU on unenhanced CT and incomplete or nondiagnostic characterization. In a patient without cancer and without prior stability, the 2017 branches distinguish 1-2 cm, >2 to <4 cm, and >=4 cm masses. | First review prior imaging: stability for >=1 year ends imaging follow-up. With no cancer history, consider dedicated adrenal CT follow-up at 12 months for a 1-2 cm mass; obtain a dedicated adrenal CT at detection for a >2 to <4 cm mass. Adenoma is supported by absolute washout >=60% or relative washout >=40%. If characterization remains indeterminate, choose 6-12 month imaging, PET/CT, biopsy or resection according to the full clinical scenario rather than the attenuation value alone. | Indeterminate is not a calibrated malignancy-risk percentage. New or enlarging lesions and larger size increase concern, but the paper states that no validated growth-rate threshold separates benign from malignant adrenal masses. | Mayo-Smith et al., JACR 2017, Fig. 1; pp.4-5 'Masses Without Diagnostic Features (>=1 to <4 cm)' and adrenal CT protocol; APW/RPW formulas and >=60%/>=40% thresholds on p.5. | ✓ |
| macroscopic-fat | Macroscopic fat (myelolipoma) | Adrenal mass containing macroscopic fat, which the 2017 ACR incidental-mass algorithm identifies as diagnostic of a myelolipoma and routes to a benign endpoint. | No additional imaging workup or follow-up is needed under this incidental-mass algorithm. Consider biochemical assessment only as clinically indicated because imaging characterization and functional status are separate questions. | Macroscopic fat is a diagnostic benign feature in the 2017 flowchart and no branch-specific malignancy percentage is supplied. Apply the stated algorithm only in its incidental, asymptomatic adult scope. | Mayo-Smith et al., JACR 2017, Fig. 1 diagnostic-benign branch; p.3 reporting considerations and p.4 'Masses With Diagnostic Benign Imaging Features' identify macroscopic fat as myelolipoma. | ✓ |
| large-mass | Large mass | Isolated adrenal mass >=4 cm with no diagnostic benign imaging feature and no history of cancer. 'Isolated' means that no other metastatic disease is identified. | Consider surgical resection without biopsy for possible primary adrenocortical carcinoma. Determine functional status and exclude pheochromocytoma before biopsy or resection; the branch is not an instruction to biopsy a possible primary adrenal cortical carcinoma. | Larger size is qualitatively more suspicious and motivates the >=4 cm branch, but the white paper does not assign a numeric malignancy probability to this category. | Mayo-Smith et al., JACR 2017, Fig. 1 >=4 cm/no-cancer branch and footnotes 1 and 3; p.5 'Masses Without Diagnostic Features (>=4 cm)'. | ✓ |
| prior-malignancy | Known prior malignancy | Known malignancy plus an adrenal mass without a diagnostic benign feature or documented >=1-year stability. The pathway considers size, whether the lesion is isolated, growth, central necrosis and the result of dedicated adrenal CT characterization. | Review priors first. For an indeterminate 1 to <4 cm mass without prior stability, obtain dedicated adrenal CT without and with contrast. Consider FDG-PET/CT or image-guided biopsy when the mass is new or enlarging, centrally necrotic, remains indeterminate, or is >=4 cm; PET/CT also evaluates occult extra-adrenal disease. Exclude pheochromocytoma before biopsy. | Metastasis is more likely in a patient with known malignancy than without it, yet the paper emphasizes that even in oncology patients most incidental adrenal masses are benign. No patient-specific numeric risk is assigned to this branch. | Mayo-Smith et al., JACR 2017, Fig. 1 cancer-history branches; pp.4-5 cancer-history pathway; p.6 PET/CT and adrenal-biopsy sections. | ✓ |

### Citações por categoria
- **benign-features**: Mayo-Smith WW, Song JH, Boland GL, et al.. Management of Incidental Adrenal Masses: A White Paper of the ACR Incidental Findings Committee (2017) — https://doi.org/10.1016/j.jacr.2017.05.001 · Mayo-Smith et al., JACR 2017, Fig. 1 and p.4 'Masses With Diagnostic Benign Imaging Features'; p.5 defines no enhancement as <10 HU change; pp.6-7 discuss functional assessment.
- **indeterminate**: Mayo-Smith WW, Song JH, Boland GL, et al.. Management of Incidental Adrenal Masses: A White Paper of the ACR Incidental Findings Committee (2017) — https://doi.org/10.1016/j.jacr.2017.05.001 · Mayo-Smith et al., JACR 2017, Fig. 1; pp.4-5 'Masses Without Diagnostic Features (>=1 to <4 cm)' and adrenal CT protocol; APW/RPW formulas and >=60%/>=40% thresholds on p.5.
- **macroscopic-fat**: Mayo-Smith WW, Song JH, Boland GL, et al.. Management of Incidental Adrenal Masses: A White Paper of the ACR Incidental Findings Committee (2017) — https://doi.org/10.1016/j.jacr.2017.05.001 · Mayo-Smith et al., JACR 2017, Fig. 1 diagnostic-benign branch; p.3 reporting considerations and p.4 'Masses With Diagnostic Benign Imaging Features' identify macroscopic fat as myelolipoma.
- **large-mass**: Mayo-Smith WW, Song JH, Boland GL, et al.. Management of Incidental Adrenal Masses: A White Paper of the ACR Incidental Findings Committee (2017) — https://doi.org/10.1016/j.jacr.2017.05.001 · Mayo-Smith et al., JACR 2017, Fig. 1 >=4 cm/no-cancer branch and footnotes 1 and 3; p.5 'Masses Without Diagnostic Features (>=4 cm)'.
- **prior-malignancy**: Mayo-Smith WW, Song JH, Boland GL, et al.. Management of Incidental Adrenal Masses: A White Paper of the ACR Incidental Findings Committee (2017) — https://doi.org/10.1016/j.jacr.2017.05.001 · Mayo-Smith et al., JACR 2017, Fig. 1 cancer-history branches; pp.4-5 cancer-history pathway; p.6 PET/CT and adrenal-biopsy sections.

## Referências cruzadas
- _fronteira compartilhada_ → [ACR Incidental Pancreatic Cyst — ACR incidental pancreatic cyst management](https://radcommons.laudos.ai/systems/acr-incidental-panc-cyst-2017.md) — Both are ACR Incidental Findings Committee white papers in the same series.

## Histórico de versões

| Data | Evento | Detalhe | Situação |
| --- | --- | --- | --- |
| 2017-08-01 | published | ACR Incidental Findings Committee adrenal white paper published. | confirmed |


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> Conteúdo de referência reescrito. Confira a publicação primária vigente. Não é dispositivo médico nem substitui o julgamento clínico. O radiologista responsável pelo laudo permanece o autor e o responsável.

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