Comments On Adrenal Gland

Metastatic carcinoma in the adrenal gland, particularly from lung, breast and kidney, is commoner than a primary neoplasm and usually detected by follow-up CT scan. Sometimes CT-guided needle core biopsy or FNA is used to make this distinction and more often primary adrenal neoplasms present either as a symptomatic or incidental mass or are characterized by their endo-crinological symptoms and signs and resultant biochemical profiles. Phaeochromocytoma is a contraindication to biopsy due to the risk of a catecholamine-induced hypertensive crisis. CT/MRI scans can assess the size, characteristics and bilaterality of adrenal lesions, helping to distinguish hyperplasia (secondary to hyperpituitarism and usually bilateral) from neoplasm but are poor at designating benignity from malignancy apart from on the basis of size. Adrenal carcinoma cells are often dysfunctional and the tumour reaches a significant size (most are >5cm/50-100g) before presentation. Histologically the best indicators of malignancy are mitoses (>5 cm/50 hpfs), diffuse growth pattern, necrosis, fibrous bands, capsular and vascular invasion. However, it can be difficult to distinguish an adenoma from a well-differentiated adrenocortical carcinoma and the term adrenocortical neoplasm may be used qualified by a morphological assessment of its likelihood to recur. Spread is to lymph nodes, liver and lung, sometimes with local invasion into kidney and inferior vena cava. Treatment is aimed at complete local excision, which may be laparoscopic for small lesions but an open thoracoabdominal approach for a larger tumour. Overall 5-year survival for adrenal carcinoma is 35%. Characteristic hormonal effects of adrenal cortical tumours are hypercortisolism (Cushing's syndrome), hyperaldosteronism (Conn's syndrome) and virilization.

Phaeochromocytoma is medullary in location, 3-5 cm in diameter and 75-150g in weight, or larger, with a pale to tan coloured cut surface. It is associated with MEN2A/2B, von Hippel Lindau disease and neurofibromatosis. Similar extra-adrenal paragangliomas are found elsewhere along sympathetic/parasympathetic nervous system sites in the retroperi-toneum, mediastinum, carotid body, middle ear and urinary bladder with variable secretory capacity and functionality, e.g. chemodectomatous head and neck paragangliomas. Adrenal phaeochromocytoma has a characteristic nested "Zellballen" pattern its cells secreting catecholamines and inducing paroxysmal symptoms of flushing, sweating, tachycardia, tremor and hypertension. Surgical excision requires careful control of blood pressure to avoid a hypertensive crisis. Overall survival is 50% with 10% bilateral or extra-adrenal or malignant. Malignant behaviour cannot be predicted histologically, with metastases being the only reliable criterion. Spread is usually to lymph nodes, then the axial skeleton, liver, lung and kidney.

Neuroblastoma and ganglioneuroblastoma are characteristically seen in infants and children and are not further considered.

Immunophenotype of adrenal neoplasms

— adrenal carcinoma: positive for cytokeratins (variable), vimentin, synaptophysin, inhibin, melan-A. CEA negative. Strong positivity for cytokeratin, EMA and CD10 would favour metastatic renal clear cell carcinoma, one of its main differential diagnoses.

— phaeochromocytoma: positive for catecholamines, chromogranin, synaptophysin, neurofilament, cytokeratins (±) and intervening S100 positive sustentacular cells.

TMN stage of adrenal cortical carcinoma: a proposed scheme is pT1 tumour confined to adrenal gland and <5cm in greatest dimension pT2 tumour confined to adrenal gland and >5 cm in greatest dimension pT3 tumour of any size, locally invasive but not involving adjacent organs pT4 tumour of any size with invasion of adjacent organs pN0 no regional lymph node metastasis pN1 metastasis in regional lymph node(s).

Other adrenal malignancy includes malignant lymphoma and melanoma usually secondary to disseminated disease. Occasional benign lesions are ganglioneuroma, adrenal cysts, adenomatoid tumour and myelolipoma.

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    What is synaptophysin inhibin melan a?
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