Table of ContentsDefinition / general | Essential features | Terminology | ICD coding | Epidemiology | Sites | Clinical features | Diagnostic criteria | Radiology images | Case reports | Treatment | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Cytology images | Positive stains | Electron microscopy description | Sample pathology report | Differential diagnosis | Board review style question #1 | Board review style answer #1 | Board review style question #2 | Board review style answer #2
Cite this page: Gonzalez RS. ACTH secreting tumors. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/pancreasacth.html. Accessed February 6th, 2023.
Definition / general
- Rare lesion mostly described in case reports
- Patients develop Cushing syndrome clinically
- Aggressive, with poor prognosis
- Recognized by IARC as ACTH producing tumor with Cushing syndrome (Lloyd: WHO Classification of Tumours of Endocrine Organs, 4th Edition, 2017)
- ICD-10: E24.3 - ectopic ACTH syndrome
- Responsible for about 15% of cases of ectopic Cushing syndrome
- May be more common in tail of pancreas
- Determined clinically, not by immunohistochemical positivity for ACTH
- 27 year old woman with ovarian and pelvic metastases (Int J Clin Exp Pathol 2015;8:15396)
- 40 year old woman with Cushing syndrome (Ann Hepatobiliary Pancreat Surg 2017;21:61)
- 41 year old woman with bilateral ovarian metastases (Int J Gynecol Pathol 2002;21:276)
- 48 year old woman with tumor secreting ACTH and possibly corticotropin releasing hormone (CRH) (Endocr Pathol 2015;26:239)
- 54 year old woman with ACTH secretion only at second relapse (J Clin Endocrinol Metab 2004;89:3731)
- Surgical excision
- Firm, gray-white, well circumscribed lesions that may measure up to 5 cm
Microscopic (histologic) description
- Appears similar to other well differentiated neuroendocrine tumors of the pancreas
- Lymphovascular and perineural invasion often present
- Focal necrosis is rare
Microscopic (histologic) images
Electron microscopy description
- Round cytoplasmic secretory granules, diameter of 100 - 300 nm, with an electron dense core (Int J Clin Exp Pathol 2015;8:15396)
Sample pathology report
- Pancreas, tail, resection:
- Pancreatic neuroendocrine tumor, WHO grade 1 (see synoptic report and comment)
- Comment: The patient’s clinical history of Cushing syndrome is noted. This may be due to ACTH secretion by this tumor. Immunohistochemical stains for synaptophysin and chromogranin are positive and the Ki67 index is approximately 2.3%.
Board review style question #1
- A 45 year old woman presents with complaints of weight gain, increased facial hair, striae on her arms and easy bruising. An abdominal CT scan shows a 4 cm mass in the tail of her pancreas. What hormone is the tumor likely secreting?
Board review style answer #1
A. ACTH. The patient is presenting with Cushing syndrome, secondary to ACTH production by her pancreas lesion (likely a neuroendocrine tumor), which leads to increased cortisol production by the adrenal glands. Pancreatic tumors do not themselves secrete cortisol.
Reference: ACTH secreting tumors
Reference: ACTH secreting tumors
Board review style question #2
- Which of the following is often seen microscopically in well differentiated pancreatic neuroendocrine tumors that secrete ACTH?
- Abundant necrosis
- Grade 3 mitotic rate
- Lymphocytic infiltration
- Perineural invasion