HIGH YIELD: Atrial Myxoma

High Yield Info. No fluff. Here's some of the key features to know (for the boards)...

GENERAL INFO

THE BASICS:

  • Benign tumor, Curable by resection

TYPICAL CLINICAL PICTURE:

SPORADIC TYPE (most common):

  • OLDER female (50 yo) presents with a SINGLE mass in her LEFT ATRIUM near the fossa ovalis, appears MOBILE . Can cause symptoms similar to mitral valve stenosis

Atrial Myxoma- Courtesy of Merck Manuals (click to open in new tab)

FAMILIAL (CARNEY COMPLEX) TYPE:

  • YOUNGER female (avg 26 yo) with MULTIPLE cardiac masses, can involve the RIGHT ATRIUM ; tend to recur more often than in sporadic myxomas.

HIGH YIELD ASSOCIATIONS:

CARNEY COMPLEX (7% of cases)= Autosomal Dominant

  1. Myxomas (atrial & cutaneous)

  2. Abnormal skin pigmentation

  3. Endocrine OVERactivity (adrenal, pituitary, thyroid)

NAME

  • Nevi, Atrial Myxoma, Ephelides

LAMB

  • Lentigenes, Atrial Myxoma, Blue nevi

BUZZ WORD(S):

  • Mobile mass in (left) atria with a myxoid stroma & atypical vessels on histology

KEY PATHOLOGY FINDINGS

Gross examination: Large, mobile, pedunculated polypoid mass arising from the atrial endocardial surface. Courtesy of Instagram user, medicaltalks

  • Ball-shaped or papillary/elongated mass attached to endothelial surface (of atrium) by a stalk (this is why it is mobile)

  • Loose myxoid stroma

  • Plump, stellate, or spindled cells arranged in cords

  • Primitive-appearing vessels

  • +/- hemorrhage/ hemosiderin & inflammatory cells in the background

A rarely seen feature, but good to know about...Heterologous elements (glands or extramedullary hematopoeisis) can be present in 2% of cases. This has NO clinical significance, but DON'T OVERCALL B9 GLANDS AS SOME SORT OF ADENOCARCINOMA!

- CLICK HERE TO EXAMINE A VIRTUAL SLIDE -

(Courtesy of PathPresenter.net - link opens in new window)

Loose myxoid stroma with delicate vessels (Click to examine virtual slide)

ANCILLARY STUDIES

(EX: ADDITIONAL TESTS TO CLUE YOU IN TO THE DIAGNOSIS)

Endothelial markers (CD31 & CD34) +
Calretinin +

(Helps DDx from atrial thrombus (which is Calretinin NEG)

NOTE: S100 is variably positive

NEG: Cytokeratin (but if heterologous glands are present, they will be +)

TOP DIFFERENTIAL DIAGNOSIS

  • ATRIAL THROMBUS: Grossly has similar appearance, but a thrombus usually is NOT MOBILE. It can have myxoid degenerative changes. Calretinin NEGATIVE

And there you have it...

Reference: Jay H. Lefkowitch. Anatomic Pathology Board Review. 2006, Elsevier Inc. pg 9.

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