Dear Editor,

A white, 32-year-old man was admitted to the emergency department with severe pain principally in the right inferior quadrant of the abdomen, abdominal distension and vomiting for one day.

Abdominal radiography, ultrasonography and computed tomography demonstrated small bowel loops distension (Figure 1A) and signs of ileo-ileal invagination associated with intraluminal nodule with fat content compatible with “intussusception head” (Figures 1B, 1C and 1D). Option was made for surgical treatment.

Anatomopathological study in association with immunohistochemical analysis diagnosed angiomyolipoma (AML) as follows:

Macroscopy: Bowel loop containing a non-encapsulated delimited, submucosal, polypoid yellowish lesion measuring 3.0 × 2.5 × 2.3 cm, with no sign of malignancy.

Microscopy: Masson's trichrome staining diagnosed AML compromising the entire intestinal wall, from the serosa to the mucosa.

Immunohistochemical analysis: Desmin, HHF 35, CD31, CD34, protein S100, smooth muscle actin 1 to 4 = positive.

Intussusception is the invagination of a proximal intestinal segment with its mesenteric fold with the corresponding vascu- larization into the lumen of the distal intestinal portion, which may lead to obstruction, inflammatory process and segmental ischemia ⁽¹1 Santos FGPL, Pereira JM, Lima RV, et al. Intussuscepção intestinal secundária a tumor do estroma gastrointestinal (GIST). Rev Imagem. 2007;29:147-51.^,22 Rosas GQ, Becker GG. Jejuno e íleo. In: D'Ippolito G, Caldana RP, editors. Gastrointestinal. Série CBR. São Paulo, SP: Elsevier; 2011. p. 173-202.⁾.

In adult individuals, this condition corresponds to about 5% of the general cases, out of which only 1% of cases cause obstruction ⁽¹1 Santos FGPL, Pereira JM, Lima RV, et al. Intussuscepção intestinal secundária a tumor do estroma gastrointestinal (GIST). Rev Imagem. 2007;29:147-51.⁾. In this age group, it is estimated that in 90% of cases one finds organic intraluminal causes called “intussusception heads” (for example, benign neoplasms such as lipoma, or malignant; adenomatous polyps or other polyp types; hamartomas) or extraluminal causes (for example, adhesions, Meckel's diverticulum)^{( 1}1 Santos FGPL, Pereira JM, Lima RV, et al. Intussuscepção intestinal secundária a tumor do estroma gastrointestinal (GIST). Rev Imagem. 2007;29:147-51.^,33 Kim YH, Blake MA, Harisinghani MG, et al. Adult intestinal intussusception: CT appearances and identification of a causative lead point. Radiographics. 2006;26:733-44.⁾.

Intussusception heads in the small bowel are most frequently associated with benign lesions, while in the colon they are most associated with either primary or secondary malignant neoplasias ⁽²2 Rosas GQ, Becker GG. Jejuno e íleo. In: D'Ippolito G, Caldana RP, editors. Gastrointestinal. Série CBR. São Paulo, SP: Elsevier; 2011. p. 173-202.⁾. The treatment is generally surgical for organic causes, complications such as obstruction and intestinal ischemia⁽²2 Rosas GQ, Becker GG. Jejuno e íleo. In: D'Ippolito G, Caldana RP, editors. Gastrointestinal. Série CBR. São Paulo, SP: Elsevier; 2011. p. 173-202.^,33 Kim YH, Blake MA, Harisinghani MG, et al. Adult intestinal intussusception: CT appearances and identification of a causative lead point. Radiographics. 2006;26:733-44.⁾.

The clinical signs of intussusception are related to the occurrence of subocclusion, obstruction and enterorrhagia⁽³3 Kim YH, Blake MA, Harisinghani MG, et al. Adult intestinal intussusception: CT appearances and identification of a causative lead point. Radiographics. 2006;26:733-44.^,44 Miliaras S, Miliaras D. Angiomyolipoma of the jejunum mimicking metastatic disease in a patient with colonic adenocarcinoma. Surgical Science. 2011;2:52-6.⁾.

Intussusceptions are classified according the involved intestinal segment, as follows: enteroenteric, colo-colic, ileocolic and ileocecal intussusception⁽¹1 Santos FGPL, Pereira JM, Lima RV, et al. Intussuscepção intestinal secundária a tumor do estroma gastrointestinal (GIST). Rev Imagem. 2007;29:147-51.^,33 Kim YH, Blake MA, Harisinghani MG, et al. Adult intestinal intussusception: CT appearances and identification of a causative lead point. Radiographics. 2006;26:733-44.⁾.

Typical radiological findings include: “target sign” and “pseudokidney sign”⁽³3 Kim YH, Blake MA, Harisinghani MG, et al. Adult intestinal intussusception: CT appearances and identification of a causative lead point. Radiographics. 2006;26:733-44.⁾. The diagnostic accuracy of ultrasonography approximates to 98%⁽²2 Rosas GQ, Becker GG. Jejuno e íleo. In: D'Ippolito G, Caldana RP, editors. Gastrointestinal. Série CBR. São Paulo, SP: Elsevier; 2011. p. 173-202.⁾, but the method is operator-dependent⁽⁵5 Marinis A, Yiallourou A, Samanides L, et al. Intussusception of the bowel in adults: a review. World J Gastroenterol. 2009;15:407-11.⁾. Computed tomography presents accuracy of 58% to 100%⁽⁵5 Marinis A, Yiallourou A, Samanides L, et al. Intussusception of the bowel in adults: a review. World J Gastroenterol. 2009;15:407-11.⁾.

AMLs are benign mesenchymal tumors containing adipose, smooth muscle, epithelial and vascular cells⁽⁴4 Miliaras S, Miliaras D. Angiomyolipoma of the jejunum mimicking metastatic disease in a patient with colonic adenocarcinoma. Surgical Science. 2011;2:52-6.^,66 Povo A, Oliveira JMS, Silva R, et al. Angiomiolipoma duodenal. Revista Portuguesa de Cirurgia. 2010;14:107-10.^–88 Lee CH, Kim JH, Yang DH, et al. Ileal angiomyolipoma manifested by small intestinal intussusception. World J Gastroenterol. 2009;15:1398-400.⁾. These tumors and other lesions such as lymphangioleiomyomatosis and clear cell lung tumors were brought together under the classification of PEComas (perivascular epithelioid cell tumors)⁽⁴4 Miliaras S, Miliaras D. Angiomyolipoma of the jejunum mimicking metastatic disease in a patient with colonic adenocarcinoma. Surgical Science. 2011;2:52-6.⁾.

The prevalence of renal angiomyolipomas ranges from 0.3% to 3%. According to the literature this tumor is sporadic in about 80% of cases, and the remaining cases are associated with lymphangioleiomyomatosis and mainly tuberous sclerosis⁽⁶6 Povo A, Oliveira JMS, Silva R, et al. Angiomiolipoma duodenal. Revista Portuguesa de Cirurgia. 2010;14:107-10.^,77 Toye LR, Czarnecki LA. CT of a duodenal angiomyolipoma. AJR Am J Roentgenol. 2002;178:92.⁾.

Extrarenal AMLs are extremely rare, and the liver is the most reported site (some other locations include the heart, lungs, retroperitoneum, mediastinum, spinal cord, mucocutaneous, parotid glands, reproductive organs regardless of sex), and its occurrence in the gastrointestinal tract is rarely described⁽⁴4 Miliaras S, Miliaras D. Angiomyolipoma of the jejunum mimicking metastatic disease in a patient with colonic adenocarcinoma. Surgical Science. 2011;2:52-6.^,66 Povo A, Oliveira JMS, Silva R, et al. Angiomiolipoma duodenal. Revista Portuguesa de Cirurgia. 2010;14:107-10.^–88 Lee CH, Kim JH, Yang DH, et al. Ileal angiomyolipoma manifested by small intestinal intussusception. World J Gastroenterol. 2009;15:1398-400.⁾ (about 50 cases)⁽⁶6 Povo A, Oliveira JMS, Silva R, et al. Angiomiolipoma duodenal. Revista Portuguesa de Cirurgia. 2010;14:107-10.^,77 Toye LR, Czarnecki LA. CT of a duodenal angiomyolipoma. AJR Am J Roentgenol. 2002;178:92.⁾.

When located in the gastrointestinal tract their radiological diagnosis is hardly achieved because of their rarity and adipose nature, similarly to lipomas which are much more frequently found⁽⁴4 Miliaras S, Miliaras D. Angiomyolipoma of the jejunum mimicking metastatic disease in a patient with colonic adenocarcinoma. Surgical Science. 2011;2:52-6.^,77 Toye LR, Czarnecki LA. CT of a duodenal angiomyolipoma. AJR Am J Roentgenol. 2002;178:92.^,88 Lee CH, Kim JH, Yang DH, et al. Ileal angiomyolipoma manifested by small intestinal intussusception. World J Gastroenterol. 2009;15:1398-400.⁾.

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