Lymphatic Anomalies

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Inside this episode

Kai, the Library's AI content creator, listened to this episode and mapped who's speaking, the chapters, key claims, and cases. Every item links to the exact moment in the recording.

AI-enriched

Who's speaking

  • Speaker 1 — host
  • Todd Ponsky — host
  • Belinda Dickey — guest
  • Denise Adams — guest
  • Steve Fishman — guest

Chapters

  • 0:00Introduction and Panel Assembly — Host Todd Ponsky introduces the episode topic of lymphatic anomalies and guest moderator Dr. Belinda Dickey from Boston Children's Hospital. Dr. Dickey introduces the expert panel: Dr. Denise Adams (pediatric hematologist-oncologist) and Dr. Steve Fishman (pediatric surgeon), both co-directors of the Vascular Anomaly Center at Boston Children's Hospital.
  • 2:12Updated Classification of Lymphatic Anomalies — Dr. Adams explains the 2014 ISSVA classification system based on John Mulligan's original framework, now incorporating genomic testing and somatic mutations. Lymphatic anomalies are divided into tumors and malformations, with malformations further stratified as macrocystic, microcystic, combined, generalized lymphatic anomaly, Gorham-Stout disease, and central conducting anomalies.
  • 4:20Clinical Importance of Proper Nomenclature — Dr. Fishman emphasizes that correct classification enables proper communication and treatment selection. He advocates abandoning outdated terms like 'cystic hygroma' and 'lymphangioma' in favor of descriptive terms like 'macrocystic lymphatic malformation' that convey the pathology and suggest therapeutic approaches.
  • 6:33Case Presentation: Truncal Macrocystic Lesion — Dr. Dickey presents a hypothetical 2-year-old with a truncal mass showing multiple cysts on ultrasound. Dr. Adams describes the interdisciplinary evaluation process including history, physical exam, and point-of-care ultrasound by interventional radiology to determine lesion depth and extent before recommending sclerotherapy for localized macrocystic disease.
  • 8:51Role of Surgery in the Modern Era — Dr. Fishman outlines four treatment options: observation, microinterventional therapy (sclerotherapy), resection, and pharmacological therapy. For localized macrocystic lesions, choice between sclerotherapy and resection depends on size, location, and predicted cosmetic outcome. Very large lesions may warrant primary resection to avoid multiple sclerotherapy sessions and residual redundant tissue.
  • 13:26Medical Therapy with mTOR Inhibitors — Dr. Adams describes the development of sirolimus (rapamycin) therapy based on PIK3CA pathway involvement in lymphatic malformations. She emphasizes that sirolimus improves quality of life, reduces pain and infection frequency in complex cases, and when used preoperatively can soften tissue to facilitate less extensive surgical resection. Dr. Fishman confirms he now routinely operates without stopping sirolimus, finding tissue more pliable and easier to work with.
  • 18:29Debate: Preoperative Medical Therapy — Dr. Dickey advocates for sirolimus pretreatment even for extra-fascial lesions before resection. Dr. Fishman agrees for complex and microcystic lesions but states he would not use sirolimus for purely macrocystic lesions, as the tissue expansion from the cysts actually facilitates surgical closure. The panel agrees that infants started on sirolimus are often observed for extended periods before any debulking unless functional impairment exists.
  • 21:30Observation as a Valid Treatment Option — In response to Todd's question, Dr. Fishman explains that observation is appropriate for non-obstructive lesions, though spontaneous resolution is rare (less than a handful of macrocystic cases in several thousand patients). He describes one dramatic case of massive cervical-mediastinal disease detected prenatally that completely resolved by one year of age. Families are counseled about anesthetic risks and that delayed treatment remains an option.
  • 27:35Follow-up Protocols and Burrough's Rule — Dr. Adams recommends individualized follow-up intervals starting monthly for anxious new parents, then extending to 3-6 months and annually as appropriate. Dr. Fishman introduces 'Burrough's rule': when history, physical, and imaging are not classic, tissue diagnosis is mandatory. He recounts cases of synovial sarcoma and metastatic neuroblastoma initially thought to be vascular lesions.
  • 31:45Sclerotherapy Technique and Safety — Dr. Dickey outlines sclerosant selection: doxycycline for macrocysts, bleomycin (with monitoring) for microcysts, and sodium tetradecyl sulfate for venous components. Dr. Fishman emphasizes critical safety principles for venous sclerotherapy: venous mapping by MR, ultrasound, or venography is essential; direct macroscopic outflow to systemic veins must be obliterated first with laser, coils, or glue to prevent fatal pulmonary embolism from induced clot.
  • 35:45Evolution of Practice and Complex Cases — Todd describes his practice evolution from resection to surgeon-performed sclerotherapy to interventional radiology-led sclerotherapy. Dr. Fishman notes that globally, most sclerotherapy is likely performed by surgeons due to limited access to specialized interventional radiology. The panel briefly discusses complex cases including central conducting anomalies and combined overgrowth syndromes that require multidisciplinary expertise.
  • 40:34Resources and Closing Summary — Dr. Adams provides contact information for Boston Children's Vascular Anomaly Center. Todd summarizes key teaching points: wide array of lymphatic anomalies require proper classification, ultrasound and MRI differentiate micro from macrocystic lesions, macrocystic lesions respond to sclerotherapy or resection, microcystic lesions typically need resection, and preoperative sirolimus softens tissue for better surgical outcomes.

Key claims

  • 2:26The ISSVA classification system was updated in 2014 to incorporate genomic testing and somatic mutations in stratifying lymphatic anomalies — Denise Adams
  • 3:06Lymphatic malformations are divided into macrocystic (larger cysts visible individually), microcystic (tiny cysts forming soft tissue mass), combined lesions, generalized lymphatic anomaly, Gorham-Stout disease, and central conducting anomalies — Denise Adams
  • 4:33Using proper nomenclature like 'lymphatic malformation' instead of outdated terms 'cystic hygroma' or 'lymphangioma' improves communication and guides appropriate treatment selection — Steve Fishman
  • 5:49Macrocystic lesions can be conceptualized as 'a bunch of grapes' where each cyst is large enough to access with a needle for sclerotherapy — Steve Fishman
  • 6:20Microcystic lesions are like a small porous sponge where individual cysts are too tiny to target with sclerotherapy, making this approach less valuable — Steve Fishman
  • 9:06Most lymphatic malformations are present at birth and visible at birth, though some can present with sudden expansion in a 2-year-old — Steve Fishman
  • 10:05Four general treatment options exist for lymphatic malformations: observation/reassurance, microinterventional therapy (sclerotherapy), resective surgery, and pharmacological therapy — Steve Fishman
  • 11:43For localized macrocystic lesions, sclerotherapy is preferred if one or two sessions can achieve durable effect without leaving a scar, versus resection for very small lesions that can be removed with minimal cosmetic impact — Steve Fishman
  • 12:30Very large macrocystic lesions extending from axilla to pelvis may warrant primary surgical resection rather than multiple sclerotherapy sessions that leave redundant skin and septal tissue requiring eventual resection anyway — Steve Fishman
  • 15:54Sirolimus (rapamycin) is an mTOR inhibitor that blocks the PIK3CA pathway, which has been shown to be a somatic mutation in many lymphatic malformations — Denise Adams
  • 16:59Sirolimus therapy improves quality of life, reduces pain, and decreases frequency of infections in patients with complicated lymphatic anomalies — Denise Adams
  • 17:41Preoperative sirolimus can soften lymphatic tissue and decrease lesion size, making surgical procedures less extensive — Denise Adams
  • 19:31Operating on patients while continuing sirolimus (rather than stopping it preoperatively) makes tissue softer and more pliable, allowing more extensive resection with better flap closure — Steve Fishman
  • 20:25Sirolimus is not useful for purely macrocystic lesions because tissue expansion from the cysts actually makes surgery easier by providing bigger flaps for closure — Steve Fishman
  • 10:08Observation and reassurance is an effective treatment option for many lymphatic malformations that are not cancers and often not dangerous — Steve Fishman
  • 22:33Spontaneous resolution of macrocystic lymphatic malformations occurs in less than a handful of cases out of several thousand patients — Steve Fishman
  • 23:27EXIT procedures are not really necessary for lymphatic lesions because they are soft and compressible, allowing intubation, unlike firm teratomas where EXIT plays a role — Steve Fishman
  • 25:11Babies with congenital lymphedema of lower extremities can have regression to the point of non-detection on physical exam, though this is uncommon — Steve Fishman
  • 25:55Lesions impinging on the airway that could cause emergency if infected or bleeding should not be observed, as delayed treatment is not safe — Steve Fishman
  • 26:20Early treatment in infancy is now favored for microcystic lesions on the face, tongue, and floor of mouth, as it likely achieves better long-term results than delayed treatment — Steve Fishman
  • 29:28Burrough's rule states that if diagnosis is not classic on history, physical, and imaging, tissue biopsy is necessary — Steve Fishman
  • 28:56Ultrasound with Doppler is the least invasive first imaging step after clinical exam, followed by MRI if diagnosis remains unclear — Belinda Dickey
  • 32:08Number of sclerotherapy treatments needed varies by lesion size and type, ranging from one treatment to multiple treatments over years — Belinda Dickey
  • 33:10Doxycycline is used for macrocystic lesions, bleomycin (with monitoring for side effects) for microcystic lesions, and sodium tetradecyl sulfate for venous components — Belinda Dickey
  • 33:40Venous sclerotherapy requires fluoroscopic venous mapping to ensure sclerosant does not extend intravascularly — Belinda Dickey
  • 34:25A small amount of ethanol systemically can cause sudden fatal pulmonary hypertension during venous sclerotherapy — Steve Fishman
  • 34:45Large venous anomalies with direct macroscopic outflow to systemic veins can result in pulmonary embolism from clot induced by sclerotherapy — Steve Fishman
  • 35:24Direct venous outflow must be obliterated first using intravenous laser, titanium coils, or glue before inducing clot with sclerotherapy to prevent fatal pulmonary embolism — Steve Fishman
  • 38:09Bleomycin use for vascular anomalies requires monitoring because early use resulted in reported cases of pneumonitis when maximum dosing was not understood — Denise Adams
  • 39:38Central conducting lymphatic anomalies present with subcutaneous chyle, eroding bones, chylous ascites, chylothorax, and chyle dripping from urethra, scrotum, vagina, or even from under toenails — Steve Fishman

Cases discussed

  • 22:59Massive cervical and mediastinal macrocystic lymphatic malformation detected prenatally with concern for airway management at birth
  • 30:35Small leg lesion initially thought to be vascular malformation, diagnosed as synovial sarcoma
  • 31:21Newborn with presumed multifocal hepatic hemangioma that was actually metastatic neuroblastoma

Points of disagreement

  • 13:32Use of sirolimus pretreatment for extra-fascial truncal lesions before resection
    • Belinda Dickey: Advocates for sirolimus pretreatment even for extra-fascial lesions before surgical resection to soften tissue and reduce extent of surgery needed
    • Steve Fishman: Would not use sirolimus for purely macrocystic lesions because tissue expansion from cysts actually facilitates surgical closure; reserves sirolimus for microcystic and complex lesions

Open questions

  • What are the long-term outcomes of sirolimus pretreatment before surgical resection compared to surgery alone?
  • What is the optimal duration of sirolimus therapy before surgical intervention?
  • Should sirolimus be continued or stopped perioperatively, and does this affect infection risk or surgical outcomes?
  • What are the long-term implications of lymphatic anomalies that appear to resolve in childhood?
  • What is the optimal follow-up interval for patients with lymphatic malformations managed with observation?
This episode was analyzed and enriched by Kai, the Library's AI content creator. Every item links to the moment it comes from — click a timestamp to listen in context.
Written for:

Massive Fetal Lymphatic Malformation That Vanished Without Treatment

The patient case from this episode, retold from presentation to outcome with the decisions made along the way. Written by Kai from the episode transcript and reviewed before publishing.

For the care team · Case narrative · AI-written, human-reviewed

Presentation

A fetus presented with extensive cervical and mediastinal macrocystic lymphatic malformation on prenatal imaging 2:26. The lesion was larger than the typical cervical lesions the team routinely managed. The imaging raised immediate concern about airway obstruction at delivery, prompting the vascular anomalies team at Boston Children's Hospital to plan their presence in the delivery room with airway expertise ready.

While EXIT procedures — ex utero intrapartum treatment maintaining placental circulation while securing the airway — are sometimes considered for large neck masses, the team noted that lymphatic lesions rarely require this approach 23:27. One of the discussants explained that these lesions are soft and compressible, and you can always intubate these children, unlike teratomas that can be firm 23:27.

The Decision Point

When the baby was born, the clinical picture diverged sharply from the prenatal imaging. The lesion was much less impressive than expected. The team faced a choice: intervene based on what the imaging had shown, or observe based on what they were actually seeing.

This is where experience shapes judgment. Most lymphatic malformations are present and visible at birth 9:06. Spontaneous resolution of macrocystic lesions is very rare 22:33. One of the discussants tells parents there is a chance of spontaneous deflation, but emphasizes these cases are uncommon 22:33. The standard teaching would favor early intervention for a lesion this size — particularly one involving the mediastinum, where infection or hemorrhage could create an airway emergency 25:55.

But the team chose observation.

What Happened

The lesion resolved completely within less than one year. At follow-up, it was undetectable on physical examination. The outcome was so unexpected that the patient's grandfather confronted one of the discussants in the newborn intensive care unit, upset that the prenatal counseling had frightened his daughter and son-in-law. The discussant apologized for being wrong but expressed gladness about the outcome, noting that while this is a great result, these cases where lesions truly resolve are very rare and it's not good to give false hope to people 22:33.

What Changed

This case illustrates a principle that runs counter to surgical instinct: lymphatic malformations are not cancers, often not dangerous, and observation with reassurance is quite effective for many patients 10:08. The team now explicitly discusses the risks of doing nothing versus the risk of intervention 10:08 — framing inaction as a legitimate treatment choice rather than a failure to treat.

The case also reinforces the limits of prenatal imaging. Macrocystic lesions can appear more alarming on fetal MRI than they prove to be at birth, and the compressibility of lymphatic tissue means that airway concerns may be overstated. The team still plans for the worst — they were in the delivery room ready to manage a difficult airway — but they no longer assume that large size on imaging mandates intervention.

For lesions that do not impinge on the airway and are not at risk of causing emergency if infected or bleeding, waiting eliminates nothing 25:55. Families are increasingly aware of the neurodevelopmental risks of repetitive anesthetics in newborns, and there is some risk to everything we do, so the choice not to do something doesn't eliminate the choice of doing it later 25:55.

The transferable judgment is this: in a well-resourced center with close follow-up, observation is not passive. It is an active treatment strategy that spares intervention in the subset of patients — small but real — who will improve without it. The key is distinguishing lesions where delayed treatment is safe from those where it is not, and having the infrastructure to monitor the difference.

Takeaways from this story

  • Spontaneous resolution of macrocystic lymphatic malformations is very rare but does occur.
  • Observation is a legitimate treatment for lymphatic malformations not threatening the airway, as delayed intervention remains an option.
  • Lymphatic lesions are soft and compressible, making EXIT procedures unnecessary even when prenatal imaging suggests airway risk.
  • Prenatal imaging can overestimate clinical severity of macrocystic lesions compared to postnatal examination.

Topic overview

A multidisciplinary discussion of lymphatic anomalies featuring pediatric hematologist-oncologist Dr. Denise Adams and pediatric surgeon Dr. Steve Fishman from Boston Children's Hospital's Vascular Anomaly Center, moderated by Dr. Belinda Dickey. The panel reviews the updated ISSVA classification system that stratifies lymphatic anomalies by phenotype and genomic mutations, distinguishing macrocystic from microcystic lesions and complex syndromes. Core clinical teaching centers on treatment selection: macrocystic lesions respond well to sclerotherapy or resection, microcystic lesions typically require resection, and complex or extensive disease benefits from mTOR inhibitor (sirolimus) pretreatment to soften tissue and reduce surgical morbidity. The discussants emphasize that observation is a valid option for many non-obstructive lesions, proper nomenclature is essential for communication and treatment planning, and safety in sclerotherapy requires understanding agent selection and venous mapping to prevent fatal pulmonary embolism.

Key takeaways

  • Macrocystic lesions respond to sclerotherapy; microcystic lesions need resection due to cyst size limiting needle access. (5:49)
  • Preoperative sirolimus softens lymphatic tissue, enabling more extensive resection with better flap closure. (17:41)
  • Early treatment of microcystic face/tongue lesions in infancy achieves better long-term outcomes than delayed intervention. (26:20)
  • Venous sclerotherapy requires fluoroscopic mapping and obliteration of direct systemic outflow to prevent fatal pulmonary embolism. (33:40)
  • Sirolimus improves quality of life and reduces infection frequency in complex lymphatic anomalies via mTOR pathway inhibition. (15:54)

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Transcript

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