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Keywords:

  • angiomyoma;
  • lower lip

ABSTRACT

  1. Top of page
  2. ABSTRACT
  3. INTRODUCTION
  4. CASE REPORT
  5. DISCUSSION
  6. REFERENCES

Angiomyolipoma (AML) in the oral cavity is extremely rare. Their histological features are characterized by admixtures of blood vessels, smooth muscles and mature adipose tissues. We report a case of sporadic AML in the lower lip of a 56-year-old man. Clinically, it presented as a mucocele-like lesion. An excised specimen showed a well-circumscribed, 1.3 cm × 1.0 cm × 0.8 cm-sized, yellowish mass, composed of blood vessels, smooth muscles and mature adipose tissues. These were not epithelioid cells and immunohistochemical stain for human melanoma black (HMB)-45 was negative. Extrarenal AML usually is not associated with tuberous sclerosis and has no HMB-45 immunoreactive cells although it shares the terminology with renal AML. It is regarded as benign. Surgical excision is considered curative.


INTRODUCTION

  1. Top of page
  2. ABSTRACT
  3. INTRODUCTION
  4. CASE REPORT
  5. DISCUSSION
  6. REFERENCES

Angiomyolipoma (AML) is a neoplasm composed of varying admixtures of blood vessels, smooth muscles and mature adipose tissues.1 This tumor is generally known as usually occurring in kidney, which is often associated with tuberous sclerosis. But, extrarenal AML including oral AML has been reported. Only eight cases of oral AML had been reported in English-language published work. So, we present a case of AML of the lower lip.

CASE REPORT

  1. Top of page
  2. ABSTRACT
  3. INTRODUCTION
  4. CASE REPORT
  5. DISCUSSION
  6. REFERENCES

A 56-year-old male patient had bleeding of the lower lip. He had no clinical features or family history of tuberous sclerosis. Past medical history was that of chronic obstructive pulmonary disease. On physical examination, he had a bluish, protruding, well-circumscribed lesion overlying normal appearing mucosa with firm consistency at the lower lip (Fig. 1). Under the clinical impression of a mucocele, excisional biopsy was performed. Grossly, the tumor was a well-circumscribed, 1.3 cm × 1.0 cm × 0.8 cm-sized yellowish mass. Histologically, the mass was a well-demarcated lesion without fibrous capsule. It was separated from the overlying epithelium. The tumor demonstrated a classic triphasic histopathology; an admixture of variable-sized blood vessels, smooth muscles and mature adipose tissues in variable amounts (Fig. 2). There were no epithelioid cells within the mass. Most of the smooth muscle components showed fascicular arrangement. No cellular atypia or mitosis was found. Most of the blood vessels had variably thickened-walls and were associated with interlacing smooth muscle. Immunohistochemical stain of smooth muscle actin and Masson–Trichrome stain helped to define smooth muscles (Fig. 3). Cells with human melanoma black (HMB)-45 immunoreactivity were not found. Based on these features, this case was diagnosed as AML arising in an extrarenal site.

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Figure 1. Lesion of lower lip. It is firm, protruding and well-circumscribed lesion (arrow). The overlying mucosa shows bluish discoloration.

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Figure 2. Histological sections show well-circumscribed nodules with variable-sized blood vessels (arrow), smooth muscle bundles (arrowhead) and mature adipose tissue (asterisk) at both (a) low- and (b) high-power views (hematoxylin and eosin; [a]×40; [b]×100).

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image

Figure 3. (a) Immunohistochemical stain for smooth muscle actin reveals thick-walled blood vessels and smooth muscles (×40). (b) Masson-trichrome stain highlights red muscle fibers and blue collagen (×40).

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DISCUSSION

  1. Top of page
  2. ABSTRACT
  3. INTRODUCTION
  4. CASE REPORT
  5. DISCUSSION
  6. REFERENCES

Angiomyolipoma usually affects the kidney and one-third of patients with renal AML are associated with tuberous sclerosis. Reports of extrarenal AML have increased, such as liver, lung, mediastinum, heart, spermatic cord, vaginal wall, fallopian tube, pharynx, larynx, nasal cavity, skin and oral cavity.2 Among extrarenal AML, hepatic AML is similar to renal AML from association with tuberous sclerosis (5–10%) and HMB-45 immunoreactivity of epithelioid myoid cells.3 Renal and hepatic AML are also considered as perivascular epithelioid cell tumor (PEComa).3 Herein, we shall consider only extrarenal AML (excluding hepatic AML) which is different from renal AML. Although extrarenal AML shows similar histopathology and shares the terminology with renal and hepatic AML, extrarenal AML differs from renal AML, clinically and pathologically. Extrarenal AML is usually not related to tuberous sclerosis. Renal AML is characterized by co-expression of melanocytic markers and smooth muscle markers and considered as a family of lesions characterized by proliferation of perivascular epithelioid cells.1,4 On the other hand, extrarenal AML lacks epithelioid cells which are immunoreactive for HMB-45 stain.2,5,6 These findings are also common in other mucosal and cutaneous AML as well as oral AML.2,5,6

Prior to our report, only eight AML of the oral cavity had been reported in the English published work. We have summarized these in Table 1 with initial clinical impression and HMB-45 immnoreactivity.6–12 Most of the oral AML were well-demarcated tumors with/without fibrous capsule. Usually they were an easily excised mass. A case reported by Ide et al.9 had ill-defined circumscription without fibrous capsule, therefore, these authors suggested the term, angiomyolipomatous hamartoma. However, these lesions consisted of the three typical mesenchymal tissues that confirmed AML and recent cases without fibrous capsule had been reported, so we included the case reported by Ide et al.9 in the oral AML category like da Silva et al.12 Oral sites affected included the hard palate, upper and lower lip, tongue and buccal mucosa.6–12 There was no sex prevalence. Most of them showed no association with tuberous sclerosis, but only one of them presented in a patient with tuberous sclerosis.11 Immunohistochemical stain for HMB-45 or cytogenetic studies were not performed in that AML case. Although a case arose in a patient with tuberous sclerosis, it cannot clarify association between tuberous sclerosis and AML. All cases in which a HMB-45 stain was performed showed negative findings including the present case, which is one of the differences between renal and extrarenal AML. Although renal AML can display perirenal fat involvement, and behave in a clinically malignant fashion in case of epithelioid AML, classic AML is regarded as benign.13 There is need of further investigation for clinicopathological characteristics of extrarenal AML, but extrarenal AML is also considered as benign. Complete excision is currently curative.

Table 1.  Clinical features of the nine oral angiomyolipoma cases reported in the English-language published work
No.ReferencesAge (years)SexLocationSize (cm)Clinical presentation or impressionDemarcation/CapsulationTuberous sclerosisHMB-45 immunoreactivity
  1. HMB-45, human melanoma black-45; M, male; F, female; NA, not available.

1Gutmann et al.739MHard palate1Palatal cystWell-demarcated/UnencapsulatedNoNA
2Yamamoto et al.862FHard palate1Benign tumorWell-circumscribed/Thinly encapsulatedNoNA
3Yamamoto et al.869FLower lip1Small massWell-circumscribed/Thinly encapsulatedNoNA
4Ide et al.960FTongue0.7Painless massIll-defined/UnencapsulatedNoNegative
5Piattelli et al.1043MHard palateNAPainless massWell-demarcated/Incomplete capsuleNoNegative
6López-López et al.1155FBuccal mucosa/Lower lip0.3–0.6Multiple fibromatosisNAYesNA
7da Silva et al.1243FUpper lip2Painful massWell-demarcated/Incomplete capsuleNoNegative
8Alvarez Alvarez et al.652MHard palateNAPainless massWell-demarcated/UnencapsulatedNoNegative
9Kim et al. (this report)54MLower lip1.3MucoceleWell-demarcated/UnencapsulatedNoNegative

Microscopically, AML should be differentiated from angiolipoma and angioleiomyoma. It is important to identify three characteristic components – thick-walled blood vessels, smooth muscle bundles and mature adipose tissues – for accurate diagnosis.

Our case of oral AML will contribute to analysis of the clinicohistopathological characteristics of these tumors.

REFERENCES

  1. Top of page
  2. ABSTRACT
  3. INTRODUCTION
  4. CASE REPORT
  5. DISCUSSION
  6. REFERENCES
  • 1
    Murphy WM, Grignon DJ, Perlman EJ. AFIP Atlas of Tumor Pathology: Tumors of the Kidney, Bladder, and Related Urinary Structures, 4th edn. Washington , DC : American Registy of Pathology, 2004.
  • 2
    Go JH. Angiomyolipoma of the nasal cavity. Korean J Pathol 2005; 39: 2846.
  • 3
    Romano F, Franciosi C, Bovo G et al . Case report of a hepatic angiomyolipoma. Tumori 2004; 90: 13943.
  • 4
    Burt AD, Portmann BC, Ferrell LD. MacSween's Pathology of the Liver, 5th edn. New York : Churchill Livingstone, 2006.
  • 5
    Shin JU, Lee KY, Roh MR. A case of a cutaneous angiomyolipoma. Ann Dermatol 2009; 21: 21720.
  • 6
    Alvarez Alvarez C, Fernández Sanromán J, Fernández Castilla M, Antón Badiola I. Sporadic oral angiomyolipoma: case report. Med Oral Patol Oral Cir Bucal 2007; 12: E3913.
  • 7
    Gutmann J, Cifuentes C, Vicuña R, Sobarzo V, Balzarini MA. Intraoral angiomyolipoma. Oral Surg Oral Med Oral Pathol 1975; 39: 9458.
  • 8
    Yamamoto K, Nakamine H, Osaki T. Angiomyolipoma of the oral cavity: report of two cases. J Oral Maxillofac Surg 1995; 53: 45961.
  • 9
    Ide F, Shimoyama T, Horie N. Angiomyolipomatous hamartoma of the tongue. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1998; 85: 5814.
  • 10
    Piattelli A, Fioroni M, Rubini C, Fiera E. Angiomyolipoma of the palate: report of a case. Oral Oncol 2001; 37: 3235.
  • 11
    López-López J, Rodríguez-de-Rivera-Campillo E, Marques-Soares MS, Finestres-Zubeldia F, Chimenos-Küstner E, Roselló-Llabrés X. Tuberous sclerosis and its oral manifestations: a clinical case. Med Oral 2004; 9: 21623.
  • 12
    da Silva AA, Carlos R, Contreras E, de Almeida OP, Lopes MA, Vargas PA. Angiomyolipoma of the upper lip: case report and review of the literature. Med Oral Patol Oral Cir Bucal 2007; 12: E1014.
  • 13
    Bostwick DG, Cheng L. Urologic Surgical Pathology, 2nd edn. Philadelphia : Mosby, 2008.