Correspondence

Case 18-1994: Tuberous Sclerosis

N Engl J Med 1994; 331:813-814September 22, 1994

Article

To the Editor:

The addendum to Case 18-1994 (May 5 issue),1 which describes a patient with tuberous sclerosis, stated that “the findings from a subsequent fine-needle aspiration biopsy of the left renal mass were consistent with an angiomyolipoma.” A computed tomographic (CT) scan of the abdomen had shown large bilateral renal masses with a predominantly fatty density.

In my view, biopsy of kidney lesions in patients with tuberous sclerosis adds little information, may be misleading, and can even be dangerous. The radiographic features of angiomyolipomas on ultrasound examination (echogenic areas) or CT scanning (areas of fatty tissue; -20 to -60 Hounsfield units) are pathognomonic2. Combined with renal cysts, these radiologic findings are typical of tuberous sclerosis3. Cellular pleomorphism is possible with angiomyolipoma, and the histologic appearance may mimic that of sarcoma4. A diagnosis based on a small and therefore non-representative amount of tissue obtained by needle biopsy may be erroneous and lead to a radical nephrectomy. Biopsy can also damage the atypical vessels of an angiomyolipoma and cause severe bleeding. Patients with tuberous sclerosis frequently have involvement of both kidneys5; they also have an approximately 10 percent risk of progressive renal failure,6 which might be increased by a needle biopsy.

Hartmut P.H. Neumann, M.D.
Klinikum der Albert-Ludwigs-Universitat Freiburg, Freiburg 79106, Germany

6 References

1. 1

   Case Records of the Massachusetts General Hospital (Case 18-1994). N Engl J Med 1994;330:1300-1306
   Full Text | Web of Science | Medline

2. 2

   Sherman JL, Hartman DS, Friedman AC, Madewell JE, Davis CJ, Goldman SM. Angiomyolipoma: computed tomographic-pathologic correlation of 17 cases. AJR Am J Roentgenol 1981;137:1221-1226
   Web of Science | Medline

3. 3

   Roach ES, Smith M, Huttenlocher P, Bhat M, Alcorn D, Hawley L. Diagnostic criteria: tuberous sclerosis complex: report of the Diagnostic Criteria Committee of the National Tuberous Sclerosis Association. J Child Neurol 1992;7:221-224
   CrossRef | Web of Science | Medline

4. 4

   Mostofi FK, Sesterhenn IA, Sobin LH, et al. Histological typing of kidney tumours. Geneva: World Health Organization, 1981.
   

5. 5

   Neumann HPH, Bruggen V, Wetterauer U, Kruse R, Blankenhorn V, Riegler P. Angiomyolipoma of the kidney and tuberous sclerosis. J Am Soc Nephrol 1992;3:300-300
   

6. 6

   Stillwell TJ, Gomez MR, Kelalis PP. Renal lesions in tuberous sclerosis. J Urol 1987;138:477-481
   Web of Science | Medline

Author/Editor Response

Dr. Burton, who cared for the patient described in Case 18-1994, replies:

To the Editor: I agree that a renal biopsy is not needed when a patient with tuberous sclerosis has findings on CT scanning that are characteristic of renal angiomyolipoma. The patient in Case 18-1994 had three dominant renal lesions. Two of the lesions replaced the upper poles of the kidneys and had a predominantly fatty density consistent with a diagnosis of angiomyolipoma. A third exophytic soft-tissue area of density arose from the lower pole of the left kidney. The attenuation of this lesion was atypical of an angiomyolipoma. The possibility of a malignant condition was considered because renal-cell carcinoma has been associated with tuberous sclerosis1-5 and may coexist with angiomyolipoma2,4. Because of this possibility and because the patient, as a candidate for lung transplantation, may need immunosuppression in the future, further investigation of the third lesion was deemed necessary.

Melvin D. Burton, M.D.
Massachusetts General Hospital, Boston, MA 02114

5 References

1. 1

   Ahuja S, Loffler W, Wegener OH, Ernst H. Tuberous sclerosis with angiomyolipoma and metastasized hypernephroma. Urology 1986;28:413-419
   CrossRef | Web of Science | Medline

2. 2

   Graves N, Barnes WF. Renal cell carcinoma and angiomyolipoma in tuberous sclerosis: case report. J Urol 1986;135:122-123
   Web of Science | Medline

3. 3

   Gutierrez OH, Burgener FA, Schwartz S. Coincident renal cell carcinoma and renal angiomyolipoma in tuberous sclerosis. AJR Am J Roentgenol 1979;132:848-850
   Web of Science | Medline

4. 4

   Taylor RS, Joseph DB, Kohaut EC, Wilson ER, Bueschen AJ. Renal angiomyolipoma associated with lymph node involvement and renal cell carcinoma in patients with tuberous sclerosis. J Urol 1989;141:930-932
   Web of Science | Medline

5. 5

   Weinblatt ME, Kahn E, Kochen J. Renal cell carcinoma in patients with tuberous sclerosis. Pediatrics 1987;80:898-903
   Web of Science | Medline