Solitary Extra-Medullary Plasmacytoma of the True Vocal Cord

Hoarseness from a cold is a familiar frustration, but for one 42-year-old man, a persistent cough and voice change led to a surprising diagnosis: a rare cancer that looked just like a benign vocal cord polyp. His story highlights how even “common” symptoms can hide serious conditions—and why never assuming a lesion is harmless matters.

The Case: A “Polyp” That Wasn’t

After a cold, the man developed progressive hoarseness and a cough that wouldn’t go away. Antibiotics for suspected laryngitis did nothing, and six months later, a laryngoscopy (a camera exam of the throat) revealed a smooth, pink growth on his right vocal cord—exactly what a benign polyp looks like. No pain, trouble swallowing, or weight loss; no swollen lymph nodes. His doctors assumed it was a polyp and removed it with a CO₂ laser during surgery.

But the pathology report changed everything: the “polyp” was a solitary extra-medullary plasmacytoma (EMP)—a rare cancer of plasma cells (white blood cells that make antibodies) that grows in soft tissue (not bone).

What Is EMP?

Plasmacytomas are uncommon, making up 5–10% of all plasma cell neoplasms. They split into two types:

Solitary bone plasmacytoma (SBP): Grows in bone (more common—40% more cases than EMP).
Extra-medullary plasmacytoma (EMP): Grows in soft tissue (like the throat, nose, or sinuses).

Ninety percent of EMPs start in the head and neck, but the larynx (voice box) is extremely rare—just 0.04–0.19% of all malignant laryngeal tumors. Even rarer? EMPs that look like benign lesions, as in this case.

Ruling Out Worse News

To confirm it was solitary (not part of multiple myeloma, a more serious plasma cell cancer), the team ran a full work-up:

Blood/urine tests: Normal serum proteins, immune cells, and kidney function.
Bone marrow biopsy: Less than 1% plasma cells (normal is under 5%).
Imaging: X-rays, a PET scan, and a skeletal survey showed no spread.

The only abnormal finding? Slightly elevated protein “light chains” in urine—common in plasma cell disorders but not enough to signal myeloma. The final diagnosis: laryngeal EMP.

Treatment: Surgery, Radiation, and Choice

Guidelines from the International Lymphoma Radiation Oncology Group are clear: radiation is the main treatment for EMP, and surgery + radiation works better than either alone to prevent recurrence. For small tumors in easy-to-reach areas (like skin or lung lesions), surgery alone might be enough—if margins are clean (no cancer left behind).

In this case, the CO₂ laser’s “sealing effect” (which kills cancer cells 2mm deep) might have removed all the tumor. But when the diagnosis came in, doctors urged radiation. The patient refused, fearing side effects. Instead, he agreed to close follow-up: every six months, a laryngoscopy to check for local recurrence and blood/urine tests to watch for systemic spread.

Five years later, he’s symptom-free. No signs of cancer returning—yet.

Why This Matters for You

EMP is tricky because it mimics benign conditions like polyps or cysts. Laryngoscopy alone can’t tell the difference—only a biopsy (tissue sample) and pathology can. Even after treatment, 10–15% of EMP cases progress to multiple myeloma, so lifelong follow-up is non-negotiable.

For this patient, luck and early action played a role: his tumor was small, in a non-sinonasal area (which has better outcomes), and he was under 65 (older age = higher risk). But his story is a warning: never ignore persistent symptoms, and always ask about biopsies for unexplained lesions—even if they look “benign.”

Reported by Ya-Li Du and Yan Yan from the Department of Otolaryngology–Head and Neck Surgery at Peking University Third Hospital in Beijing.

References

Venkatesulu B, Mallick S, Giridhar P, Upadhyay AD, Rath GK. Pattern of care and impact of prognostic factors on the outcome of head and neck extramedullary plasmacytoma: a systematic review and individual patient data analysis of 315 cases. Eur Arch Otorhinolaryngol 2018;275:595–606. doi:10.1007/s00405-017-4817-z
Tsang RW, Campbell BA, Goda JS, Kelsey CR, Kirova YM, Parikh RR, et al. Radiation therapy for solitary plasmacytoma and multiple myeloma: guidelines from the International Lymphoma Radiation Oncology Group. Int J Radiat Oncol Biol Phys 2018;101:794–808. doi:10.1016/j.ijrobp.2018.05.009
Ge S, Zhu G, Yi Y. Extramedullary plasmacytoma of the larynx: literature review and report of a case who subsequently developed acute myeloid leukemia. Oncol Lett 2018;16:2995–3004. doi:10.3892/ol.2018.8992
Mihashi S, Jako GJ, Incze J, Strong MS, Vaughan CW. Laser surgery in otolaryngology: interaction of CO2 laser and soft tissue. Ann N Y Acad Sci 1976;267:263–294. doi:10.1111/j.1749-6632.1976.tb41614.x

doi:10.1097/CM9.0000000000000303

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