29 Sep 2020

9/3/20: Lymphangioleiomyomatosis (LAM)

PGY3 Gloria Wu presented a case of a 35 y/o F with history of obesity, hypothyroidism, Castleman’s disease and depression/bipolar disorder presents with abdominal distention and discomfort x 2 weeks.  Her symptoms are associated with SOB, orthopnea and dyspnea on exertion as well as loss of appetite and fatigue.  Patient also reports 30 pounds of unintentional weight loss over the past 2 months.  Home medications include Aristada IM injections for bipolar disorder and Levothyroxine daily.  She lives with family and denies any alcohol/tobacco/drug use.

Vitals stable, BMI 52.6.  Exam significant for decreased breath sounds throughout bilateral posterior lung fields, distended, mildly tender to palpation abdomen with positive fluid wave and 1+ pitting edema from ankles to mid-shins bilaterally.

CBC: WBC 5.8 > Hb 12.8/Hct 40.5 <Plt 380

CMP:

Na 140/K 4.4/Cl 105/HCO3 23/BUN 11/Cr 0.92 <Glucose 84

ALP 84>T.protein 4.6/Albumin 2.7/AST 15/ALT 18/Tbili 0.3/Dbili 0.2

Coags:PT 13.7, INR 1.06, PTT 30.1

TSH 4.4 (normal 0.27-4.2), FT4 1.22 (normal 0.93-1.7)

Pro-BNP 27

CXR with moderate L pleural effusion.

US Abdomen showed unremarkable kidney and liver; moderate to large volume ascites.

Paracentesis performed with the following results:

  • Cell count: 399 (38% PMN, 21% Lymphs, 29% Monocytes, 1% Plasma cells)
  • BF Albumin 0.6 (Serum Albumin 2.7)
  • Glucose 99
  • Triglycerides 1734 (serum TG 86)
  • BF Cx negative
  • AFB BF Culture negative
  • BF Fungal Culture negative

Thoracentesis performed with the following results:

  • Cell count: 1085 (69% PMNs, 10% Lymph, 2% Monocyte, 1% Eosinophils, 2% plasma cells)
  • Glucose 102
  • BF LDH 363 (Serum LDH 194)
  • BF Protein 3.4 (Serum protein 5)
  • Triglycerides 1701
  • Pathology: large highly vacuolated cells present
  • BF ADA 23.1 U/L
  • BF Culture negative
  • AFB Body fluid culture negative
  • BF fungal culture negative

Infectious workup:

  • Bcx negative x2
  • UA with trace protein, negative leuk (0-3 WBC) and moderate blood (6-10 RBC)
  • UCx negative
  • HIV negative
  • Acute hepatitis panel negative
  • Lactate 0.8
  • Procalcitonin 0.06
  • Quant gold negative
  • RPR negative

Hematology workup:

  • Reticulocyte percentage 0.96%
  • Abs Retic: 36.38 x10^9/L
  • Iron panel
    • Iron 22 mcg/dL (normal 50-160)
    • TIBC 239 mcg/dL (normal 250-430)
    • Iron sat 9% (normal 15-50%)
    • Ferritin 51 ng/mL(normal 15-240)
  • Fibrinogen 603 (normal 239-439)
  • DDimer >20 (normal <0.49)
  • LDH 172
  • K/L: 14.8/14.4 = 1.03
  • SPEP: no monoclonal proteins identified

Rheum workup:

  • ANA negative
  • dsDNA negative

HRCT revealed innumerable small thin-walled cystic structures throughout the bilateral lung with an upper lobe predominance.  Small b/l pleural effusions.

PET Scan showed conglomerate hypermetabolic LNs in the bilateral retroperitoneum, measuring 9.3cm on the R and 8.0cm on the L, SUV max 4.4.  Diffusely hypermetabolic appearance of the axial skeleton. Splenomegaly.

LN biopsy performed with final path read for smooth muscle tumor.

Given the HRCT findings along with chylous pleural and ascitic fluid and biopsy showing smooth muscle tumor, there is high likelihood Lymphangioleiomyomatosis (LAM) is the diagnosis.

Treatment: After infection was ruled out, the patient was started on Sirolimus for treatment of LAM.  She was able to improve and discharged with Pulmonology and Oncology outpatient follow up.

Take home points:

  1. Chylous Asites = TG >200 suggests it; Common causes: malignancy (lymphomas, neuroendocrine, sarcomas, leukemias), cirrhosis, trauma/surgery, TB, congenital malformation
  2. Lymphangioleiomyomatosis (LAM) is a rare disease that almost exclusively affects reproductive age women (age 30-40) with abnormal proliferation of smooth muscles cells.  It is characterized by lung cysts, lymphatic abnormalities, angiomyolipomas (kidneys), and retroperitoneal lymphadenopathy.  This is associated with tuberous sclerosis complex.
  3. Diagnose with HRCT and clinical findings/biopsy.  Can send for VEGF-D levels which will be elevated In these patients.
  4. Management: encourage healthy diet and exercise, avoid estrogen containing medications, bronchodilators, Sirolimus (mTOR inhibitor), consider lung transplant if severe.

Review Article:

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