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 (IHC and special stains) | Electron microscopy description | Differential diagnosis | Board review style question #1 | Board review answer #1 | Board review style question #2 | Board review answer #2
Cite this page: Gonzalez RS. ACTH secreting tumors. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/pancreasacth.html. Accessed September 23rd, 2020.
Definition / general
- Rare lesion mostly described in case reports
- Patients develop Cushing syndrome clinically
- Aggressive, with poor prognosis
- Recognized by IARC: WHO Classification of Tumours of Endocrine Organs, 4th Edition, 2017 as “ACTH producing tumor with Cushing syndrome”
- 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
Positive stains (IHC and special stains)
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)
- Non ACTH secreting pancreatic neuroendocrine tumor: must be determined on clinical grounds, though ACTH positivity by immunohistochemistry is rare in these
- Pancreatic acinar cell carcinoma
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 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.
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
Board review answer #2
D. Perineural invasion. These tumors, which are commonly WHO grade 2, often show lymphovascular and perineural invasion. Focal necrosis may sometimes be seen.