Tumor Surgery > Tumor Education > Soft Tissue Tumors > Soft Tissue Tumor Types

Myxoma is a rare benign soft tissue tumor composed of fibroblasts embedded in abundant myxoid stroma. Myxomas have a gelatinous consistency, resembling the fetal umbilical cord. They may be derived from modified fibroblast cells. Sometimes, malignant tumors can undergo myxoid degeneration, making difficult to distinguish from myxomas on an MRI. In other words, malignant myxoid tumors can have a similar appearance as a myxoma on an MRI which is also similar to a ganglion cyst.

CLINICAL DATA

A benign soft tissue tumor
Usually solitary
Usually affects age 40 to 70 years
Slight female predilection
Multiple myxomas are rare
Multiples myxomas are associated with Carney complex:
Autosomal dominant disorder
Multiple cardiac and skin myxomas
Skin pigmentation
Endocrine involvement
Bone tumors
Mazabraud syndrome
Rare condition of multiple myxomas with polyostotic fibrous dysplasia
Multiple intramuscular myxomas localized in one side of the body
Polyostotic fibrous dysplasia appears before the myxomas
May be associated also with McCune-Albright syndrome
Three forms
Intramuscular myxoma (most common but still quite rarely seen)
Hypocellular
Sparse or inconspicuous vasculature
Bland spindle to stellate vasculature
Arises in skeletal muscle
Juxta-articular myxoma
Morphologically similar to intramuscular myxoma
Occurs immediately adjacent to a large joint
Commonly associated with cystic degeneration of adjacent articular cartilage
Thought to be related to a ganglion cyst
Digital myxoma
Digital lesion usually found in the finger
Composed of fibroblasts which elaborate a copious myxoid matrix

DIFFERENTIAL DIAGNOSIS

Low grade myxofibrosarcoma
Nerve sheath tumor
Angiomyxoma
Leiomyoma
Leiomyosarcoma
Ganglion Cyst

CLINICAL PRESENTATION

Signs/Symptoms
Intramuscular myxoma
Slowly growing
Painless intramuscular mass
Juxta-articular myxoma
Similar to intramuscular, near a big joint
Pain
Digital myxoma
Small
Painful

Prevalence
Digital and intramuscular myxoma more commonly affect females
Juxta-articular myxomas affect primarily males
Relatively uncommon
Affect primarily older adults (40-70 years of age)

Sites
Intramuscular myxoma
Thigh or gluteal region are most common sites
Also occur in the shoulder girdle and arm
Juxta-articular myxoma
Knee
Shoulder
Elbow
Hip
Digital myxomas are found on the finger

RADIOGRAPHIC PRESENTATION

Plain x-ray
Nonspecific soft tissue mass
Internal calcifications are rare

CT scan
Well-defined, homogenous soft tissue mass
Tissue attenuation, less than normal muscle

MRI
Well-defined mass
Homogenous signal
Intermediate signal intensity on T1W similar to muscle
High signal intensity on T2W indicative of fluid
Thin rim of higher signal around the mass on T1W
Post contrast heterogeneous enhancement on T1W
Enhance with contrast as opposed to a ganglion cyst

Fig. 1 Axial CT reconstruction of a myxoma of the knee, shows an anterior medial mass isointense with muscle.

Fig. 2 Axial MRI of a myxoma of the upper extremity shows a homogeneous intermediate signal mass on T1W images (Fig. 2), heterogenous enhancement on post gadolinium (Fig. 3), and homogeneous high signal on T2W images (Fig. 4).

PATHOLOGY

Gross
Mucoid-gelatinous
Well circumscribed
Sometimes present with infiltrative borders
Rarely exceeds the 13 cm Ø

Microscopic
Intramuscular myxoma
Fairly well circumscribed but often infiltrates distally and proximally with what looks like a tail
Appears infiltrative
Merges with surrounding skeletal muscle and fascial tissue
Very hypocellular
Bland uniform hypocellular fibroblasts (spindle cells) in a mucinous bluish staining background
Juxta-articular myxoma
Morphologically identical to intramuscular myxoma
Digital myxoma
Similar feature to intramuscular
Hypercellulary is more common
Overlying epidermis may be ether hyperplastic or athrophic
Does not infiltrate into deeper tissues
Lesion merges imperceptibly with dermal connective tissue

Fig. 5 Gross histology of myxoma showing a uniform gelatinous surface from the production of myxoid stroma

IMMUNOCHEMISTRY

Positive for spindle cells
Vimentin
CD 34 (50%)
Mucoid matrix
Alcian blue
Mucicarmine
Colloidal iron
Negative
S-100
Desmin

Fig. 6-7 Microscopic: Low power (Fig. 6) and high power magnification (Fig. 7) of a myxoma shows bland hypocellular uniform spindle shaped cells arranged in abundant myxoid stroma. There are no mitotic figures and no necrosis. The cells are very uniform.

PROGNOSIS

Biological behavior
Intramuscular myxoma
Rare local recurrence
No metastases
Recurring lesions are not destructive
Juxta-articular myxoma
Up to 30% rate of local recurrence---->infiltrative nature leads to recurrences
Even with complete excision
No metastasis
Digital myxoma
30% chance of local recurrence
No metastasis

TREATMENT

Excision, rarely recurs if complete excised
Cellular type appear to have same indolent behavior even after complete excision

Fig. 8 Intraoperative photograph of resection of a myxoma from a forearm.

Office Locations

Morristown Medical Center

Carol G. Simon Cancer Center

100 Madison Avenue

2nd Floor

Morristown, NJ 07960

Phone: 833-292-BONE (2663)
Fax: 973-898-1636
Email: drjameswittig@gmail.com

Get Directions >>

Services & Specialties

Pediatric and Adult Bone Sarcomas
Soft Tissue Sarcomas
Benign Bone Tumors
Benign Soft Tissue Tumors
Childhood Sarcomas
Shoulder Tumors
Cryosurgery
Radiofrequency Ablation
Special Surgeries
Diagnosis and Treatment

Testimonials

"Thank you from the bottom of my heart for your excellent care...I wish you a very long and productive professional life so that more people can benefit from your expertise, so that more people can get a second chance to live their lives to the fullest."

Irina B.

"I am writing to you to thank you for everything you and your team have done for me. I cannot tell you how fortunate I feel that I am in your care. It gives me the peace of mind that I have you as my doctor. Your knowledge and expertise is greatly appreciated. You truly are the best! Thank you!"

-Sincerely,
JG

Dear Dr. Wittig,
I am writing at a loss to find adequate words to thank you for all that you have done for me. You were so generous to give up your time on a weekend to operate on my femur. I believe that this made a vast difference in my life. Your skills as a diagnostician and surgeon have given me an opportunity to have a better life. At a time like this, it is comforting to be treated with kindness and skill. Thank you for sharing your gifts with me.

Dear Dr. Wittig,
I'm so thrilled with your diagnosis, and thankful too! If you're ever in S. Orange and would like to visit "The Gate" for a pint, I'd be happy to personally escort you. You'll get the VIP treatment. Thank you so very much for your attention and professionalism.

Dear Dr. Wittig,
I can't thank you, and your team enough for making our son, who recently underwent surgery (removing a tumor on his pelvis), feel so comfortable and at ease. As did you, with my family, addressing all our questions, and concerns. We knew he as in the best possible hands. You are a wonderful, compassionate Doctor....We are so grateful to have such a gifted Dr. taking care of him.
Sincerely,
Sandy

Dear Dr. Wittig,

Thank-you so very much for being my surgeon for that chondrosarcoma, for saving my life! And I have learned over the months (from other doctors...) that I was very fortunate to have you as a surgeon.

I think that I should have been more cheerful and clear upon receiving the good news from you during the visit on Wednesday.--I was just that I've been so anxious, worried, tense, confused from 6 months of various treatments -- prostate 45 day radiation, gall stone passing, kidney stone matters that have been happening these past months.

In driving home after the news today, I've begun feeling increasingly released, cheerful...able at long last to get on fully with my life.

You, your staff, that hospital...have set the bar for health care so much higher than I could have imagined.

With Deepest Gratitude!

Robert

Good evening Dr. Wittig,

I hope you are doing well this evening and hope you have a restful weekend with your family. It was a pleasure meeting you in person. After meeting you, I can understand why you and Sheeraz are close friends and colleagues, especially how highly Sheeraz spoke of you! You are kind and down to earth. Also, you and Sheeraz are not only amazing and talented doctors, but you are compassionate and empathetic to the needs of your patients and families, which often lacks in the world of medicine. I wanted to be a doctor, but I really can't deal with the sight of blood, like I mentioned to Sheeraz. Both of you are great role models how family centered care should be and how I strive and want to be with my little patients at Sloan.

I appreciate everything you have done for my Uncle. I am grateful to Sheeraz for recommending you! I hope you and your family are always happy and healthy, so you can continue to great things to impact the quality of life of others...

Thanks so much again for everything NYU familia!

Kind Regards,
Mariyam

On May 10th I had the pleasure of meeting Dr. Wittig for the first time. This was an extremely stressful time for me since I had received several reports regarding my cancer diagnosis. Upon meeting Dr, Wittig I immediately knew I was in good hands. His calm demeanor & straightforward manner were very comforting to me. He laid out how he was going to proceed with the operation, how long it would take, & followup. He has been a source of comfort to me thru out this ordeal & I know I could not be in a better place with him. His support staff of nurses, is top notch. Their attention to detail, answering questions we may have, are always done in a timely manner. Without the ease of working with Dr. James Wittig, I can tell you. I would not feel as confident with my situation as I do. He is truly a very special human being. Sincerely, Karolyn

"Thank you for helping me through the toughest time in my life!"

- Eric P.

"I can't thank you enough for everything you've done for me!"

- Kyle B.

"Unbelievable! Thank you!"

-Amanda S.