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PubMed This is a summary of 13 peer-reviewed journal articles Updated
Radiology · Lymphatic Malformation

Getting the Right Diagnosis

At a Glance

An MRI is the gold standard for diagnosing a lymphatic malformation, revealing clear, fluid-filled cysts. To identify the underlying genetic cause, like a PIK3CA mutation, doctors must test tissue directly from the malformation using a biopsy, rather than relying on a standard blood test.

Getting an accurate diagnosis is the first step toward a clear treatment plan. Because many vascular anomalies look similar on the surface, doctors rely on advanced imaging and, in some cases, genetic “mapping” of the tissue itself to confirm exactly what your child has [1][2].

The Gold Standard: MRI

While an ultrasound is often the first test used because it is quick and painless, an MRI (Magnetic Resonance Imaging) is the “gold standard” for lymphatic malformations (LMs) [2].

  • Mapping the Territory: An MRI provides a high-resolution map of exactly where the malformation sits [2][3]. It shows how the LM weaves around muscles, nerves, and vital structures like the airway, which is essential for safety and surgical planning [2][4].
  • Seeing the “Fluid”: On an MRI report, you may see the term T2 hyperintensity [5]. This simply means the area glows brightly on the scan, which tells the radiologist it is filled with clear lymphatic fluid rather than solid tissue [5][6].
  • Fluid-Fluid Levels: Radiologists look for “layers” of different types of fluid within the cysts. Seeing these levels is a classic sign of an LM [5].

Telling Malformations Apart

It is common for LMs to be confused with other conditions. A specialist radiologist will look for specific “tells” to differentiate them:

Condition Appearance on Imaging Key Differentiator Timeline
Lymphatic Malformation (LM) Large or small fluid-filled cysts [5]. No “blood flow” seen inside the cysts [5]. Usually present and detectable at birth [7].
Venous Malformation (VM) Spongy channels filled with slow-moving blood [8]. Often contains phleboliths (small, stony calcifications) [8][1]. Present at birth but may grow proportionally [2].
Infantile Hemangioma A solid “lump” of rapidly growing blood vessels [8]. Shows intense blood flow and contrast “enhancement” [8][1]. Typically appears a few weeks after birth and grows rapidly [8].

Why Blood Tests Aren’t Enough

If your doctor recommends genetic testing, they are looking for a somatic mutation—specifically in the PIK3CA gene [9][10].

It is important to understand that a standard blood test will likely come back “normal” [11]. This is because the genetic “glitch” is only present in the cells inside the malformation (this is called mosaicism) [11][12]. To find the mutation, the lab usually needs a small sample (biopsy) of the affected tissue [11][13].

How the biopsy is taken: Doctors rarely perform a separate procedure just to get this tissue. Instead, they typically take a small sample during a planned surgery or sclerotherapy procedure to spare the child an extra intervention [11][13].

Finding this specific mutation is becoming more common because it can open the door to precision medicine, which you can read about in Treatment Options and Strategies.

Common questions in this guide

Why is an MRI necessary if my child already had an ultrasound for a lymphatic malformation?
While an ultrasound is a quick first step, an MRI is the gold standard because it provides a high-resolution map of the malformation. It shows exactly how the cysts weave around muscles, nerves, and airways, which is crucial for safety and surgical planning.
What does T2 hyperintensity mean on my child's MRI report?
T2 hyperintensity simply means that the area glows brightly on the MRI scan. For a lymphatic malformation, this tells the radiologist that the cysts are filled with clear lymphatic fluid rather than solid tissue.
How do doctors tell the difference between a lymphatic malformation and an infantile hemangioma?
Lymphatic malformations appear as fluid-filled cysts with no internal blood flow and are usually present at birth. In contrast, infantile hemangiomas are solid lumps of rapidly growing blood vessels that show intense blood flow and typically appear a few weeks after birth.
Why might a standard blood test come back normal for a genetic mutation?
The genetic mutation that causes a lymphatic malformation is usually only present in the cells inside the malformation itself, a condition known as mosaicism. Therefore, a standard blood test will likely be normal, and a tissue biopsy is needed to find the mutation.
How is tissue collected for genetic testing of a lymphatic malformation?
Doctors rarely perform a separate procedure just to collect tissue. Instead, they typically take a small sample during an already planned surgery or sclerotherapy procedure to spare the child an extra medical intervention.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.Does the MRI show 'fluid-fluid levels,' and how does that confirm it is a lymphatic malformation rather than a venous one?
  2. 2.Why is an MRI necessary if we have already done an ultrasound?
  3. 3.If we do genetic testing, when and how will the tissue biopsy be collected?
  4. 4.Are there any signs of 'phleboliths' (calcifications) in the imaging that might point toward a different diagnosis?
  5. 5.Can you explain the 'T2 hyperintensity' on my child's report and what it means for the type of fluid inside the cysts?

Questions For You

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References

References (13)
  1. 1

    Low-Flow Vascular Malformation Pitfalls: From Clinical Examination to Practical Imaging Evaluation--Part 1, Lymphatic Malformation Mimickers.

    White CL, Olivieri B, Restrepo R, et al.

    AJR. American journal of roentgenology 2016; (206(5)):940-51 doi:10.2214/AJR.15.15793.

    PMID: 26999565
  2. 2

    Contribution of magnetic resonance imaging to the prenatal diagnosis of common congenital vascular anomalies.

    Crivelli L, Millischer AE, Sonigo P, et al.

    Pediatric radiology 2021; (51(9)):1626-1636 doi:10.1007/s00247-021-05031-w.

    PMID: 33891148
  3. 3

    Prenatal diagnosis of intraconal lymphatic malformation on fetal magnetic resonance imaging.

    Cheung CSY, Yang E, Robertson RL, Mantagos IS

    Journal of AAPOS : the official publication of the American Association for Pediatric Ophthalmology and Strabismus 2020; (24(2)):113-115 doi:10.1016/j.jaapos.2019.12.005.

    PMID: 31982618
  4. 4

    Fetal and postnatal magnetic resonance imaging in the assessment of patients with extensive cervicofacial lymphatic malformations.

    Schultz R, Kalajoki-Helmiö T, Kyrklund K, et al.

    Pediatric radiology 2026; (56(4)):767-776 doi:10.1007/s00247-025-06477-y.

    PMID: 41296036
  5. 5

    [Analysis of MRI and clinical characteristics for pediatric head, neck, and facial lymphatic malformations].

    Chen J, Chen W, Ke S, et al.

    Lin chuang er bi yan hou tou jing wai ke za zhi = Journal of clinical otorhinolaryngology head and neck surgery 2025; (39(7)):646-651 doi:10.13201/j.issn.2096-7993.2025.07.008.

    PMID: 40555490
  6. 6

    Vaginal discharge caused by lymphatic malformation identified by lymphoscintigraphy combined with T2-weighted magnetic resonance imaging.

    Tang G

    Journal of vascular surgery cases and innovative techniques 2020; (6(1)):1-5 doi:10.1016/j.jvscit.2019.10.003.

    PMID: 32025595
  7. 7

    Splenic cystic lymphangioma in adults: A rare case report from Syria.

    Hussein Al-Janabi M, Abodest R, Adnan Alshabab M, et al.

    Annals of medicine and surgery (2012) 2022; (80()):104152 doi:10.1016/j.amsu.2022.104152.

    PMID: 36045834
  8. 8

    [Oral angiomas].

    Lorette G, Goga D, Le Touze A, et al.

    Presse medicale (Paris, France : 1983) 2016; (45(2)):251-7.

    PMID: 26857083
  9. 9

    A somatic activating NRAS variant associated with kaposiform lymphangiomatosis.

    Barclay SF, Inman KW, Luks VL, et al.

    Genetics in medicine : official journal of the American College of Medical Genetics 2019; (21(7)):1517-1524 doi:10.1038/s41436-018-0390-0.

    PMID: 30542204
  10. 10

    Evolving medical treatment for vascular malformation.

    Pang C, Lee R, Nisbet R, et al.

    Phlebology 2026; (41(3)):190-200 doi:10.1177/02683555251361663.

    PMID: 40708269
  11. 11

    Characterization and Childhood Tumor Risk Assessment of Genetic and Epigenetic Syndromes Associated With Lateralized Overgrowth.

    Griff JR, Duffy KA, Kalish JM

    Frontiers in pediatrics 2020; (8()):613260 doi:10.3389/fped.2020.613260.

    PMID: 33392121
  12. 12

    PIK3CA vascular overgrowth syndromes: an update.

    Hughes M, Hao M, Luu M

    Current opinion in pediatrics 2020; (32(4)):539-546 doi:10.1097/MOP.0000000000000923.

    PMID: 32692051
  13. 13

    Non-hotspot PIK3CA mutations are more frequent in CLOVES than in common or combined lymphatic malformations.

    Brouillard P, Schlögel MJ, Homayun Sepehr N, et al.

    Orphanet journal of rare diseases 2021; (16(1)):267 doi:10.1186/s13023-021-01898-y.

    PMID: 34112235

This page explains diagnostic imaging and genetic testing for lymphatic malformations for educational purposes only. Always consult your child's medical team to interpret specific MRI reports and biopsy results.

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