Case 21: An unusual and fatal cause of Cushing’s syndrome

Original case by Thomas Dacruz et al

Mrs. XX, a 60-year-old woman was hospitalised with 5-month history of worsening fatigue, leg swelling, and difficulty in walking. Her past medical history included primary hypothyroidism and hypertension. She had been diagnosed with an acinic cell carcinoma of the left parotid gland, which was resected 3 years prior to current admission. She was under follow-up of the surgical team with no obvious evidence of disease recurrence or relapse at the time of presentation.

On examination in medical assessment unit, she had florid features of CS including central obesity, plethoric face, skin thinning, purplish abdominal striae, and proximal muscle weakness. Her blood pressure was elevated with rest of the general physical and systemic examination being unremarkable.

Q How will you investigate this patients ?

  1. First 8:00 am cortisol to rule out exogenous vs endogenous Cushing’s
  2. Next step would be to confirm the diagnosis of Cushing’s with Overnight dexamethasone suppression test

Reports

  1. ONDST– 28 mcg/dl (High)
  2. LDDST- 20 mcg/dl (high)

Q What would be the next step ?

To confirm ACTH dependent vs ACTH independent Cushing’s. I would do a ACTH level for the same

ACTH- 106 pg/ml

Q What is the next step ?

This is ACTH dependent Cushing’s, I would do a MRI Sella with contrast

Magnetic Resonance Image of the Pituitary. It showed normal pituitary gland.

Q What is the next step ?

Most likely Ectopic Cushing’s. MRI is normal and ACTH is >90 pg/ml- strongly in favour of ectopic Cushing’s.  What is the potassium , I would ask ?

Serum Potassium – 2.6 meq/l

With this Potassium, all evidence point to Ectopic Cushing’s.

Q What would be the next step ?

Ideally an IPSS would be required to confirm ectopic Cushing’s. However, the evidence points towards Ectopic Cushing’s. So I would investigate for presence of Ectopic Cushing’s. I would do a CT chest, abdomen and pelvis.

Abdomen/Pelvis/Thorax CT. It shows a lytic lesion on the left ischium bone suggestive of a metastatic carcinoma. A collection of gas around the sigmoid colon was noticed which was suggestive of perforated sigmoid diverticulitis.

Q Next step ?

I would consider doing a biopsy of the bone lesion

Biopsy of ischial lesion showed features consistent with a metastatic poorly differentiated acinic cell carcinoma with negative staining for ACTH. However, the previously resected primary parotid tumour of acinic cell carcinoma were stained positively for ACTH.

 

Q What is the final diagnosis ?

Ectopic ACTH-Secreting Primary parotid tumor.

Q How will you treat the patient ?

Since the patient is probably having florid Cushing’s, I would consider doing a bilateral adrenalectomy.

Our patient was commenced on metyrapone therapy on day 6 of admission with a gradual up-titration of the dose. The course of her disease was aggressive with subsequent development of intestinal perforation. Interestingly, she had minimal symptoms and signs on clinical examination suggestive of intestinal perforation with this diagnosis being only established based on the radiological investigations.

She later developed sepsis and was managed in intensive care unit. Unfortunately, despite the best possible care her condition continued to deteriorate and she died due to complications related to her ectopic ACTH related CS secondary to a metastatic salivary gland tumour.

Q Is intestinal perforation common in Cushing’s ?

Yes  Cushing’s especially exogenous Cushing’s can present with intestinal perforation and sepsis.

LEARNING POINTS

  1. Carcinoma of parotid gland can be associated with Cushing’s Syndrome
  2. Intestinal perforation can be a complications of Cushing’s syndrome.

 

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