CASE-LETTER
Localized Massive Lymphedema Masquerading as an Anterior Abdominal Mass Mimicking a Liposarcoma
M
assive localized lymphedema (MLL) is a term used to describe a benign overgrowth of connective tissue in morbidly obese patients, which is characterized by fibrotic and edematous fibroadipose tissue.1 In a few patients, it may present with massive localized collections of lymphedema mimicking liposarcoma.2 MLL is most often found in women.3 The most common location for these lesions is the proximal medial aspect of the extremities, although other locations have been reported including abdomen, scrotum, suprapubic region, lateral thighs and popliteal fossa.2 The lesion may clinically mimic liposarcoma and has been called pseudosarcoma as a result of that, but histopathology always reveals a benign process with complete lack of nuclear atypia. The entity has distinctive diagnostic features, but may be misdiagnosed by those unfamiliar with it. Histologically, it can be mistaken for a well-differentiated liposarcoma (WDL) because it was initially described in almost 60% of the reported cases.3 Imaging appearance of MLL is characteristic, and knowledge of this entity should allow an accurate diagnosis in the appropriate clinical setting.4 Although grossly and radiologically diffuse, these lesions are nevertheless confined to the superficial epifascial space of the skin and subcutaneous tissue with muscle sparing. This useful distinction during CT or MR imaging helps to differentiate MLL from other edematous entities.5 A 71-year-old morbidly obese female patient with diabetics and hypertension was referred to the radiology department for assessment of a progressive abdominal swelling (Figure 1), which was clinically diagnosed as liposarcoma with skin pigmentation of 1-year duration. Postintravenous contrast CT of the abdomen and pelvis showed a 26 3 20 3 10-cm ill-defined and nonencapsulated mass seen in the subcutaneous fat of the anterior abdominal wall. The lesion was infiltrative in appearance with clear separation from the anterior abdominal wall muscles. Internally, there were multiple unenhanced and hyperdense septal lines that are blurred but uninterrupted. It was clearly noted, in the sagittal reconstruction images, that the related skin thickening is more evident in the caudal aspect of the adherent pendulous abdominal wall, which is considered to be the dependent part in walking and sitting position (Figure 2). Ultrasound examination showed branching well-defined echolucent lines (edematous connective tissue septa) that separate well-defined fat lobules in the epifascial space but with no clear masses in this area. Those are corresponding to the blurred septal hyperdense lines seen on CT examination (Figure 3). The lesion was subsequently incised, and histopathologic examination showed an acanthotic epidermis with underlying connective tissue marked by edematous dermis and subcutaneous tissue containing scattered prominent and dilated lymphatic vessels. The interstitial cells were benign with no evidence of a lymphangioma (Figure 3). A final diagnosis of MLL was made. Diagnosis of MLL or pseudosarcoma of the anterior abdominal wall is a challenging one both clinically and
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FIGURE 1. Clinical picture of the patient at presentation. Note the extremely obese abdomen and lower limbs in addition to the presence of a pendulous mass on anterior abdominal wall.
radiologically. Distinction from other abdominal wall sarcomas is of prime importance and has great implications on the patient’s outcome. Hence, the awareness of its radiological and pathological characteristics is essential for this distinction.
FIGURE 2. Postintravenous contrast CT of the abdomen and pelvis axial images: 26 3 20 3 10-cm ill-defined, infiltrative nonencapsulated mass in the subcutaneous fat of the anterior abdominal wall with clear separation from the anterior abdominal wall muscles. Internally, there are multiple unenhanced hyperdense septal lines.
The American Journal of the Medical Sciences
Volume 347, Number 1, January 2014
Case-Letter
Figure 2, are supportive diagnostic findings which differentiate it from other neoplastic processes. In patients suffering from morbid obesity and presenting with an anterior abdominal mass, the possibility of MLL should be considered in the differential diagnosis and investigated. Both histopathologist and radiologist should be aware of the historadiological features, which can help to differentiate this lesion from a WDL. These features include the lack of radiological lesional enhancement and the absence of muscle and fascia invasion by the lesional tissue in addition to the described histopathologic morphology of lymphedema.
Mohamed S. El-Sharkawy, MD Ammar C. Al-Rikabi, MD Nawarah AlArfaj, MD Faris M. Al Mugaren, MBBS FIGURE 3. Localized massive lymphedema. Note the presence of significant dermal interstitial edema (arrowhead) with adjacent markedly dilated lymphatic vessels. Hematoxylin and eosin stain 3200.
Histopathology usually reveals a benign process with lack of nuclear atypia. Although MLL has distinctive diagnostic features, it may be misdiagnosed as sarcoma by those who are unfamiliar with it. MLL consists of a thickened epidermis with marked expansion of the dermis and lymphangiectasia in the absence of atypical stromal cells, adipocytes or endothelial cells. Based on these findings, MLL can be clearly distinguished from malignant lesion such as WDL.2,3 Radiologically, there is usually a diffuse edema involving the skin and subcutaneous tissue without extension to muscle. Although the lesion is distinct, those unfamiliar with it may consider other differentials on the basis of the imaging results. The picture is, however, not typical of a soft-tissue sarcoma, and the lesion is usually composed of subcutaneous fat but with no evidence of lesional enhancement. Although the histology may be mistaken for a WDL, the imaging does not support this. The underlying muscle and fascia are intact, and there is no evidence of visceral or omental herniation from the inguinal region.4 To the best of our knowledge, this is one of a very few reports that describes the ultrasound and CT findings of MLL.2,3 The well-defined outlines of the edematous septa in the anterior abdominal wall fat inside the mass plus the gravity-dependent thickening of the subcutaneous fat and related skin, as shown in
Ó 2013 Lippincott Williams & Wilkins
Department of Radiology (MSE-S), Department of Pathology (32) (AMA-R), Division of Plastic Surgery (NA), Department of Surgery, Plastic Surgery Unit, (FMAM), King Saud University, King Khalid University Hospital, Riyadh, Kingdom of Saudi Arabia The authors have no financial or other conflicts of interest to disclose. The expenses of the staining, histological processing of the specimen and radiological investigations were covered by the College of Medicine, King Saud University. The costs of typing the manuscript and illustration were self-financed by the authors themselves. REFERENCES 1. Goshtasby P, Dawson J, Agarwal N. Pseudosarcoma: massive localized lymphedema of the morbidly obese. Obes Surg 2006;16:88–93. 2. Wu D, Gibbs J, Corral D, et al. Massive localized lymphedema: additional locations and association with hypothyroidism. Hum Pathol 2000; 31:1162–8. 3. Farshid G, Weiss SW. Massive localized lymphedema in the morbidly obese: a histologically distinct reaction lesion simulating liposarcoma. Am J Surg Pathol 1998;22:1277–83. 4. Khanna M, Naraghi AM, Salonen D, et al. Massive localized lymphedema: clinical presentation and MR imaging characteristics. Skeletal Radiol 2011;40:647–52. 5. Szuba A, Rockson SG. Lymphedema: anatomy, physiology and pathogenesis. Vasc Med 1997;2:321–6.
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Localized Massive Lymphedema Masquerading as an Anterior Abdominal Mass Mimicking a Liposarcoma
M
assive localized lymphedema (MLL) is a term used to describe a benign overgrowth of connective tissue in morbidly obese patients, which is characterized by fibrotic and edematous fibroadipose tissue.1 In a few patients, it may present with massive localized collections of lymphedema mimicking liposarcoma.2 MLL is most often found in women.3 The most common location for these lesions is the proximal medial aspect of the extremities, although other locations have been reported including abdomen, scrotum, suprapubic region, lateral thighs and popliteal fossa.2 The lesion may clinically mimic liposarcoma and has been called pseudosarcoma as a result of that, but histopathology always reveals a benign process with complete lack of nuclear atypia. The entity has distinctive diagnostic features, but may be misdiagnosed by those unfamiliar with it. Histologically, it can be mistaken for a well-differentiated liposarcoma (WDL) because it was initially described in almost 60% of the reported cases.3 Imaging appearance of MLL is characteristic, and knowledge of this entity should allow an accurate diagnosis in the appropriate clinical setting.4 Although grossly and radiologically diffuse, these lesions are nevertheless confined to the superficial epifascial space of the skin and subcutaneous tissue with muscle sparing. This useful distinction during CT or MR imaging helps to differentiate MLL from other edematous entities.5 A 71-year-old morbidly obese female patient with diabetics and hypertension was referred to the radiology department for assessment of a progressive abdominal swelling (Figure 1), which was clinically diagnosed as liposarcoma with skin pigmentation of 1-year duration. Postintravenous contrast CT of the abdomen and pelvis showed a 26 3 20 3 10-cm ill-defined and nonencapsulated mass seen in the subcutaneous fat of the anterior abdominal wall. The lesion was infiltrative in appearance with clear separation from the anterior abdominal wall muscles. Internally, there were multiple unenhanced and hyperdense septal lines that are blurred but uninterrupted. It was clearly noted, in the sagittal reconstruction images, that the related skin thickening is more evident in the caudal aspect of the adherent pendulous abdominal wall, which is considered to be the dependent part in walking and sitting position (Figure 2). Ultrasound examination showed branching well-defined echolucent lines (edematous connective tissue septa) that separate well-defined fat lobules in the epifascial space but with no clear masses in this area. Those are corresponding to the blurred septal hyperdense lines seen on CT examination (Figure 3). The lesion was subsequently incised, and histopathologic examination showed an acanthotic epidermis with underlying connective tissue marked by edematous dermis and subcutaneous tissue containing scattered prominent and dilated lymphatic vessels. The interstitial cells were benign with no evidence of a lymphangioma (Figure 3). A final diagnosis of MLL was made. Diagnosis of MLL or pseudosarcoma of the anterior abdominal wall is a challenging one both clinically and
84
FIGURE 1. Clinical picture of the patient at presentation. Note the extremely obese abdomen and lower limbs in addition to the presence of a pendulous mass on anterior abdominal wall.
radiologically. Distinction from other abdominal wall sarcomas is of prime importance and has great implications on the patient’s outcome. Hence, the awareness of its radiological and pathological characteristics is essential for this distinction.
FIGURE 2. Postintravenous contrast CT of the abdomen and pelvis axial images: 26 3 20 3 10-cm ill-defined, infiltrative nonencapsulated mass in the subcutaneous fat of the anterior abdominal wall with clear separation from the anterior abdominal wall muscles. Internally, there are multiple unenhanced hyperdense septal lines.
The American Journal of the Medical Sciences
Volume 347, Number 1, January 2014
Case-Letter
Figure 2, are supportive diagnostic findings which differentiate it from other neoplastic processes. In patients suffering from morbid obesity and presenting with an anterior abdominal mass, the possibility of MLL should be considered in the differential diagnosis and investigated. Both histopathologist and radiologist should be aware of the historadiological features, which can help to differentiate this lesion from a WDL. These features include the lack of radiological lesional enhancement and the absence of muscle and fascia invasion by the lesional tissue in addition to the described histopathologic morphology of lymphedema.
Mohamed S. El-Sharkawy, MD Ammar C. Al-Rikabi, MD Nawarah AlArfaj, MD Faris M. Al Mugaren, MBBS FIGURE 3. Localized massive lymphedema. Note the presence of significant dermal interstitial edema (arrowhead) with adjacent markedly dilated lymphatic vessels. Hematoxylin and eosin stain 3200.
Histopathology usually reveals a benign process with lack of nuclear atypia. Although MLL has distinctive diagnostic features, it may be misdiagnosed as sarcoma by those who are unfamiliar with it. MLL consists of a thickened epidermis with marked expansion of the dermis and lymphangiectasia in the absence of atypical stromal cells, adipocytes or endothelial cells. Based on these findings, MLL can be clearly distinguished from malignant lesion such as WDL.2,3 Radiologically, there is usually a diffuse edema involving the skin and subcutaneous tissue without extension to muscle. Although the lesion is distinct, those unfamiliar with it may consider other differentials on the basis of the imaging results. The picture is, however, not typical of a soft-tissue sarcoma, and the lesion is usually composed of subcutaneous fat but with no evidence of lesional enhancement. Although the histology may be mistaken for a WDL, the imaging does not support this. The underlying muscle and fascia are intact, and there is no evidence of visceral or omental herniation from the inguinal region.4 To the best of our knowledge, this is one of a very few reports that describes the ultrasound and CT findings of MLL.2,3 The well-defined outlines of the edematous septa in the anterior abdominal wall fat inside the mass plus the gravity-dependent thickening of the subcutaneous fat and related skin, as shown in
Ó 2013 Lippincott Williams & Wilkins
Department of Radiology (MSE-S), Department of Pathology (32) (AMA-R), Division of Plastic Surgery (NA), Department of Surgery, Plastic Surgery Unit, (FMAM), King Saud University, King Khalid University Hospital, Riyadh, Kingdom of Saudi Arabia The authors have no financial or other conflicts of interest to disclose. The expenses of the staining, histological processing of the specimen and radiological investigations were covered by the College of Medicine, King Saud University. The costs of typing the manuscript and illustration were self-financed by the authors themselves. REFERENCES 1. Goshtasby P, Dawson J, Agarwal N. Pseudosarcoma: massive localized lymphedema of the morbidly obese. Obes Surg 2006;16:88–93. 2. Wu D, Gibbs J, Corral D, et al. Massive localized lymphedema: additional locations and association with hypothyroidism. Hum Pathol 2000; 31:1162–8. 3. Farshid G, Weiss SW. Massive localized lymphedema in the morbidly obese: a histologically distinct reaction lesion simulating liposarcoma. Am J Surg Pathol 1998;22:1277–83. 4. Khanna M, Naraghi AM, Salonen D, et al. Massive localized lymphedema: clinical presentation and MR imaging characteristics. Skeletal Radiol 2011;40:647–52. 5. Szuba A, Rockson SG. Lymphedema: anatomy, physiology and pathogenesis. Vasc Med 1997;2:321–6.
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