Case Report
First Report of Recurrent Intramuscular Lipoma after Decompression Surgery of the Lumbar Spine Stephan Klessinger1,2 Marc-Eric Halatsch2
Wolfgang Freund3
Georg Karpel-Massler2
1 Department of Neurosurgery, Nova Clinic, Biberach, Germany 2 Department of Neurosurgery, University of Ulm, Ulm, Germany 3 Department of Diagnostic and Interventional Radiology, University
Christian Wirtz2
Dietmar Thal4
Address for correspondence Stephan Klessinger, MD, Department of Neurosurgery, Nova Clinic, Eichendorffweg 5, Biberach 88400, Germany (e-mail: [email protected]; [email protected]).
of Ulm, Ulm, Germany 4 Laboratory of Neuropathology, University of Ulm, Ulm, Germany
Abstract
Keywords
► lipoma ► spine surgery ► spinal canal stenosis
Intramuscular or infiltrating lipomas are rare. We present a 58-year-old man with an intramuscular lipoma developing after decompression surgery for lumbar spinal canal stenosis. One year after macroscopically complete lipoma resection, an even bigger recurrent tumor had to be removed. The lumbar paraspinal musculature is a very uncommon site for an intramuscular lipoma. A relation between surgery and the growth and recurrence of an intramuscular lipoma has not been described previously in the literature.
Introduction Lipomas are the most frequent benign mesenchymal neoplasms.1 They are composed of mature fat tissues, commonly found in the superficial subcutaneous layers of the extremities and trunk.2 A lipoma may occasionally be found within the muscle (intramuscular/intermuscular or infiltrating lipoma). Intramuscular lipomas are rare.1 In most reported cases, the tumors involved the extremities and trunk or rarely affected different muscles of the head and neck region.1 An intramuscular lipoma is a benign neoplasm that concerns both clinicians and pathologists because of its large size, deep location, and infiltrating growth that has led to its description as an infiltrating lipoma.3 Typically, benign tumors show a clear margin; however, the sometimes infiltrative growth pattern of this tumor can mimic that of a malignant one. Its growth can have an effect on the number of muscle fibers, although it never metastasizes.3 The mechanisms of their infiltrative growth are not fully understood. Aberrant highmobility group proteins during tumor development have been proposed to play a role.4,5
received December 16, 2013 accepted after revision February 11, 2014
The lumbar paraspinal musculature is a very uncommon site for the development of a lipoma. A relationship between surgery and the growth and recurrence of an intramuscular lipoma has not yet been described in the literature. We report a case of a de novo intramuscular lipoma after surgical decompression of a lumbar spinal canal stenosis using an interspinous distraction device and short-term tumor recurrence.
Case Report In January 2008, a 58-year-old man presented with a spinal canal stenosis L4–L5 and neurogenic claudication but no neurologic deficit. The patient was in generally good condition. There was no spine surgery in the history. In May 2009, interlaminotomy L4–L5 with decompression of the neural structures and implantation of an interspinous distraction device was performed. Magnetic resonance imaging (MRI) studies were available from October 2007, 2 years before surgery, and from April 2009 (i.e., 1 month before surgery; ►Fig. 1). Even in retrospect, no lipoma could be detected on these scans.
© Georg Thieme Verlag KG Stuttgart · New York
DOI http://dx.doi.org/ 10.1055/s-0034-1376193. ISSN 2193-6315.
Downloaded by: Washington University. Copyrighted material.
J Neurol Surg A
Recurrent Intramuscular Lipoma
Klessinger et al.
Two years later, in January 2011, recurrent complaints arose. The MRI at this time (February 2011) demonstrated the correct position of the interspinous device, a relative spinal canal stenosis and disc protrusions but also a de novo lipoma (►Fig. 2). In a second operation in October 2011, the interspinous distraction device was removed and an L4 laminectomy was performed. The lipoma with its sub- and epifascial portions was removed completely. The histopathology report confirmed the diagnosis of lipoma. Fibrotic parts and muscle fibers were described. Six months after the second operation, a new swelling in the area of the scar was noticed (►Fig. 3), and again the patient reported low back pain, irradiating to both legs, with paraesthesia in the upper thighs but no motor deficit. The reason for the swelling, pain, and intermittent sensory loss was a recurrence of the lipoma, which was demonstrated by MRI (►Fig. 4) in November 2012, 1 year after the macroscopically complete removal of the first lipoma. Because the patient stayed abroad for a longer time, the surgery of the recurrent lipoma could only take place in July 2013. The histopathology report again confirmed the diagnosis of a lipoma. No signs of malignancy were found. Again the adipose
tissue was focally interspersed with skeletal muscle fibers, some of them were atrophic (►Fig. 5). A consistent follow-up including an early MRI was recommended because a further recurrence is likely. Unfortunately, the patient has not come in for a follow-up examination.
Discussion A lipoma is the most common type of soft tissue tumor, and solitary lipomas have been classified into two types: cutaneous/superficial and deep-seated/subfascial.3 Little is known about the etiology or histogenesis of intramuscular lipomas. They are relatively rare compared with superficial lipomas, and they have been reported to comprise 1.8% of all fatty tumors.3 The proper management of lipomas is excision. Intramuscular location makes removal more technically challenging and may require the resectioning of some surrounding muscle to ensure adequate resection margins. Because the treatment would be dramatically different, intramuscular lipomas need to be distinguished from liposarcomas by imaging.6 The modality of choice is MRI.7 The proposed criteria6,8,9 indicating malignancy are a large lesion
Fig. 2 Magnetic resonance imaging 2 years after the first operation (February 2011). The correct position of the interspinous distraction device (white arrows on the prominent black susceptibility artifact surrounding the device) is demonstrated. Now the intramuscular and sub- and epifascial lipoma (black arrows) manifests in the access area of the former operation. It is clearly demarcated and exhibits a capsule and some space-occupying effect with skin bulging. On the transverse images, intratumoral muscle fibers (hypointense strands) are visible. (A) Sagittal T2. (B) Sagittal T1. (C) Axial T2, level L5. (Courtesy of Dr. Heike Jäger, Ulm, Germany.) Journal of Neurological Surgery—Part A
Downloaded by: Washington University. Copyrighted material.
Fig. 1 Magnetic resonance imaging 1 month before the first surgery (April 2009) reveals the spinal canal stenosis L4–L5, some epidural lipomatosis (white arrows), and fatty degeneration of the paraspinal muscles (black arrow), but no paraspinal lipoma is visible. (A) Sagittal T2. (B) Sagittal T1. (C) Axial T2, level L4–L5. (Courtesy of Dr. Karin Nüssle-Kügele, Ulm, Germany.)
Fig. 3 Swelling in the scar area (November 2012).
diameter > 10 cm (perhaps already > 3 cm according to Bidault et al9), < 75% fatty tissue, presence of septa with swirling aspect, nodular areas, and nonadipose mass. Of these criteria, the visible septa with some swirling aspect (►Fig. 4)
Klessinger et al.
and the size > 3 cm were the only suspect features in our case. However, because there was no contrast enhancement and the typical interspersion of muscle fibers and adipose mass, it was decided to treat the tumor as being probably benign. The peculiarity of this case is the size and the localization of the lipoma in the lumbar paraspinal musculature and the well-documented rapid growth following surgery. Lipomas occurring in deep locations or those having unusual features may be confused with liposarcoma.10 The mechanisms of their infiltrative growth are not fully understood.3 The growth of the lipoma in this case was clearly infiltrative. The bigger part of the tumor was found subfascially, the other part subcutaneously, with clear margins and the aspect of a capsule on MRI. The origin of the tumor remained unclear. Because of the infiltrative growth and the presence of muscular tissue in the histopathologic specimen, the lesion was classified as a deep-seated muscular lipoma. Typically, even intramuscular lipomas do not exhibit atypical features.3 Sometimes the infiltration of the tumor can be seen and lipocytes are admixed to skeletal muscle fibers in various ratios,3 like in our case (►Fig. 5). Microscopically, an intramuscular lipoma is composed of mature lipocytes, the same as in lipomas found in other areas. Macroscopically,
Fig. 4 Magnetic resonance imaging 1 year after the second operation (laminectomy and complete removal of the lipoma) was performed (November 2012). An even bigger recurrent lipoma has now grown (white arrows) and reaches ventrally into the spinal canal. Dorsally, the lipoma reaches the subcutis and is responsible for the skin swelling (Fig. 3). The space-occupying lesion is clearly demarcated on the sagittal images and has a capsule but no perifocal edema. It exhibits hyperintense fatty signal intensity in T1- and T2-weighted images and is hypointense after fat saturation; however, there is no clear-cut border to the paraspinal muscles on axial images, with muscle fibers clearly extending into the lipomatous tissue. There is no relevant contrast enhancement. Striate areas of higher signal intensity after contrast medium application (black arrows) are due to muscle parenchyma and septa. (A) Sagittal T2. (B) Sagittal T1. (C) Axial T2, level L5. (D) Sagittal short tau inversion recovery. (E) Sagittal T1 (fat saturated) with contrast medium. (F) Axial T1 (fat saturated) with contrast medium. Journal of Neurological Surgery—Part A
Downloaded by: Washington University. Copyrighted material.
Recurrent Intramuscular Lipoma
Recurrent Intramuscular Lipoma
Klessinger et al. after herniorrhaphy, a revision operation revealed a large lipoma of the spermatic cord.16 However, a lipoma of the spermatic cord is a common condition of the male population,17 whereas a lipoma in the lumbar paraspinal musculature is so far unknown. To the best of our knowledge, this is the first report of such a condition. The peculiarity of this report lies in the growth, size, and recurrence of a lipoma that developed in the postoperative period. The factors that may have influenced its growth remain unclear.
Conclusion
Fig. 5 (A) Histologic confirmation of the intramuscular lipoma with numerous well-differentiated mature adipocytes within the skeletal muscle tissue in a representative tissue section covering the lipoma and parts of the bordering skeletal muscle. (B, C) Even within the groups of large number adipocytes resembling the pattern of mature adipose tissue, small bundles of skeletal muscle fibers were observed (black arrows). (C) At the high-power level the skeletal muscle fibers were identified morphologically by the sarcoplasm-associated localization of the nuclei. Calibration bar in (C) corresponds to (A) 5,000 µm, (B) 1,000 µm, and (C) 100 µm.
intramuscular lipomas are not always as well circumscribed as the superficial type.3 Therefore, intramuscular recurrence is common.11–14 The rapid growth of the lipoma, however—in this case within a year—remains outstanding. The mechanisms for increased growth tendency of such lipomas are still under debate.1,15 Multiple theories have been suggested as an underlying cause that provoke the uncontrolled growth of giant cell lipomas,1 involving the role of endocrine, dysmetabolic, and genetic factors. Most authors propose microtrauma or muscle damage that causes rupture of the fibrous septa and anchorage connections between the skin and deep fascia, thus allowing the adipose tissue to proliferate.1,3,15 Fat cell overgrowth due to muscular damage is not uncommon and has been reported in several orthopedic diseases such as muscular dystrophy and rheumatoid arthritis, as well as in other joint diseases and various neuropathies.3 Although dorsal surgery of the lumbar spine certainly always generates muscle injury, it almost never actually results in the rapid growth of a lipoma. An interrelation with the interspinous distraction device cannot be proved. The lipoma started to grow after the implantation of the interspinous distraction device, but the recurrence occurred after the removal of the implant. The medical literature contains only one report about the growth of a lipoma in the postoperative period. Twenty years Journal of Neurological Surgery—Part A
References 1 Lahrach K, el Kadi KI, Mezzani A, Marzouki A, Boutayeb F. An
2
3
4
5
6
7
8
9
10 11
12
13
unusual case of an intramuscular lipoma of the biceps brachii. Pan Afr Med J 2013;15:40 Phalen GS, Kendrick JI, Rodriguez JM. Lipomas of the upper extremity. A series of fifteen tumors in the hand and wrist and six tumors causing nerve compression. Am J Surg 1971;121(3): 298–306 Mori K, Chano T, Matsumoto K, Ishizawa M, Matsusue Y, Okabe H. Type-selective muscular degeneration promotes infiltrative growth of intramuscular lipoma. BMC Musculoskelet Disord 2004;5:20 Tallini G, Dal Cin P, Rhoden KJ, et al. Expression of HMGI-C and HMGI(Y) in ordinary lipoma and atypical lipomatous tumors: immunohistochemical reactivity correlates with karyotypic alterations. Am J Pathol 1997;151(1):37–43 Tkachenko A, Ashar HR, Meloni AM, Sandberg AA, Chada KK. Misexpression of disrupted HMGI architectural factors activates alternative pathways of tumorigenesis. Cancer Res 1997;57(11): 2276–2280 Jones AP, Lewis CJ, Dildey P, Hide G, Ragbir M. Lipoma or liposarcoma? A cautionary case report. J Plast Reconstr Aesthet Surg 2012;65(1):e11–e14 El Ouni F, Jemni H, Trabelsi A, et al. Liposarcoma of the extremities: MR imaging features and their correlation with pathologic data. Orthop Traumatol Surg Res 2010;96(8):876–883 Meyer KA, Bancroft LW, Dietrich TJ, Kransdorf MJ, Peterson JJ. Imaging characteristics of benign, malignant, and infectious jaw lesions: a pictorial review. AJR Am J Roentgenol 2011;197(3): W412–421 Bidault F, Vanel D, Terrier P, et al. Liposarcoma or lipoma: does genetics change classic imaging criteria? Eur J Radiol 2009;72(1): 22–26 Weiss SW. Lipomatous tumors. Monogr Pathol 1996;38:207–239 Uemura T, Suse T, Yokoyama T, Mitsukawa N, Yoshikawa A. Intramuscular benign lipoma of the temporalis muscle. Scand J Plast Reconstr Surg Hand Surg 2002;36(4):231–234 Pélissier A, Sawaf MH, Shabana AH. Infiltrating (intramuscular) benign lipoma of the head and neck. J Oral Maxillofac Surg 1991; 49(11):1231–1236 Mattel SF, Persky MS. Infiltrating lipoma of the sternocleidomastoid muscle. Laryngoscope 1983;93(2):205–207
Downloaded by: Washington University. Copyrighted material.
The rapid growth and recurrence of an intramuscular benign lipoma after decompression of the lumbar spinal canal is a rare cause of pain by compression of the surrounding structures including the neural elements in the spinal canal. The lipoma can reach dimensions that result in a visible and palpable swelling of the skin.
Recurrent Intramuscular Lipoma
Klessinger et al.
16 Vashu R, Subramaniam M. Large lipoma of the spermatic cord
of the head and neck. Case report and literature review. Arch Otolaryngol Head Neck Surg 1986;112(11):1210–1212 15 Allen B, Rader C, Babigian A. Giant lipomas of the upper extremity. Can J Plast Surg 2007;15(3):141–144
presenting as post-operative recurrent hernia in a middle aged gentleman: a case report. Cases J 2009;2:8500 17 Nasr AO, Tormey S, Walsh TN. Lipoma of the cord and round ligament: an overlooked diagnosis? Hernia 2005;9(3):245–247
Downloaded by: Washington University. Copyrighted material.
14 Scherl MP, Som PM, Biller HF, Shah K. Recurrent infiltrating lipoma
Journal of Neurological Surgery—Part A
First Report of Recurrent Intramuscular Lipoma after Decompression Surgery of the Lumbar Spine Stephan Klessinger1,2 Marc-Eric Halatsch2
Wolfgang Freund3
Georg Karpel-Massler2
1 Department of Neurosurgery, Nova Clinic, Biberach, Germany 2 Department of Neurosurgery, University of Ulm, Ulm, Germany 3 Department of Diagnostic and Interventional Radiology, University
Christian Wirtz2
Dietmar Thal4
Address for correspondence Stephan Klessinger, MD, Department of Neurosurgery, Nova Clinic, Eichendorffweg 5, Biberach 88400, Germany (e-mail: [email protected]; [email protected]).
of Ulm, Ulm, Germany 4 Laboratory of Neuropathology, University of Ulm, Ulm, Germany
Abstract
Keywords
► lipoma ► spine surgery ► spinal canal stenosis
Intramuscular or infiltrating lipomas are rare. We present a 58-year-old man with an intramuscular lipoma developing after decompression surgery for lumbar spinal canal stenosis. One year after macroscopically complete lipoma resection, an even bigger recurrent tumor had to be removed. The lumbar paraspinal musculature is a very uncommon site for an intramuscular lipoma. A relation between surgery and the growth and recurrence of an intramuscular lipoma has not been described previously in the literature.
Introduction Lipomas are the most frequent benign mesenchymal neoplasms.1 They are composed of mature fat tissues, commonly found in the superficial subcutaneous layers of the extremities and trunk.2 A lipoma may occasionally be found within the muscle (intramuscular/intermuscular or infiltrating lipoma). Intramuscular lipomas are rare.1 In most reported cases, the tumors involved the extremities and trunk or rarely affected different muscles of the head and neck region.1 An intramuscular lipoma is a benign neoplasm that concerns both clinicians and pathologists because of its large size, deep location, and infiltrating growth that has led to its description as an infiltrating lipoma.3 Typically, benign tumors show a clear margin; however, the sometimes infiltrative growth pattern of this tumor can mimic that of a malignant one. Its growth can have an effect on the number of muscle fibers, although it never metastasizes.3 The mechanisms of their infiltrative growth are not fully understood. Aberrant highmobility group proteins during tumor development have been proposed to play a role.4,5
received December 16, 2013 accepted after revision February 11, 2014
The lumbar paraspinal musculature is a very uncommon site for the development of a lipoma. A relationship between surgery and the growth and recurrence of an intramuscular lipoma has not yet been described in the literature. We report a case of a de novo intramuscular lipoma after surgical decompression of a lumbar spinal canal stenosis using an interspinous distraction device and short-term tumor recurrence.
Case Report In January 2008, a 58-year-old man presented with a spinal canal stenosis L4–L5 and neurogenic claudication but no neurologic deficit. The patient was in generally good condition. There was no spine surgery in the history. In May 2009, interlaminotomy L4–L5 with decompression of the neural structures and implantation of an interspinous distraction device was performed. Magnetic resonance imaging (MRI) studies were available from October 2007, 2 years before surgery, and from April 2009 (i.e., 1 month before surgery; ►Fig. 1). Even in retrospect, no lipoma could be detected on these scans.
© Georg Thieme Verlag KG Stuttgart · New York
DOI http://dx.doi.org/ 10.1055/s-0034-1376193. ISSN 2193-6315.
Downloaded by: Washington University. Copyrighted material.
J Neurol Surg A
Recurrent Intramuscular Lipoma
Klessinger et al.
Two years later, in January 2011, recurrent complaints arose. The MRI at this time (February 2011) demonstrated the correct position of the interspinous device, a relative spinal canal stenosis and disc protrusions but also a de novo lipoma (►Fig. 2). In a second operation in October 2011, the interspinous distraction device was removed and an L4 laminectomy was performed. The lipoma with its sub- and epifascial portions was removed completely. The histopathology report confirmed the diagnosis of lipoma. Fibrotic parts and muscle fibers were described. Six months after the second operation, a new swelling in the area of the scar was noticed (►Fig. 3), and again the patient reported low back pain, irradiating to both legs, with paraesthesia in the upper thighs but no motor deficit. The reason for the swelling, pain, and intermittent sensory loss was a recurrence of the lipoma, which was demonstrated by MRI (►Fig. 4) in November 2012, 1 year after the macroscopically complete removal of the first lipoma. Because the patient stayed abroad for a longer time, the surgery of the recurrent lipoma could only take place in July 2013. The histopathology report again confirmed the diagnosis of a lipoma. No signs of malignancy were found. Again the adipose
tissue was focally interspersed with skeletal muscle fibers, some of them were atrophic (►Fig. 5). A consistent follow-up including an early MRI was recommended because a further recurrence is likely. Unfortunately, the patient has not come in for a follow-up examination.
Discussion A lipoma is the most common type of soft tissue tumor, and solitary lipomas have been classified into two types: cutaneous/superficial and deep-seated/subfascial.3 Little is known about the etiology or histogenesis of intramuscular lipomas. They are relatively rare compared with superficial lipomas, and they have been reported to comprise 1.8% of all fatty tumors.3 The proper management of lipomas is excision. Intramuscular location makes removal more technically challenging and may require the resectioning of some surrounding muscle to ensure adequate resection margins. Because the treatment would be dramatically different, intramuscular lipomas need to be distinguished from liposarcomas by imaging.6 The modality of choice is MRI.7 The proposed criteria6,8,9 indicating malignancy are a large lesion
Fig. 2 Magnetic resonance imaging 2 years after the first operation (February 2011). The correct position of the interspinous distraction device (white arrows on the prominent black susceptibility artifact surrounding the device) is demonstrated. Now the intramuscular and sub- and epifascial lipoma (black arrows) manifests in the access area of the former operation. It is clearly demarcated and exhibits a capsule and some space-occupying effect with skin bulging. On the transverse images, intratumoral muscle fibers (hypointense strands) are visible. (A) Sagittal T2. (B) Sagittal T1. (C) Axial T2, level L5. (Courtesy of Dr. Heike Jäger, Ulm, Germany.) Journal of Neurological Surgery—Part A
Downloaded by: Washington University. Copyrighted material.
Fig. 1 Magnetic resonance imaging 1 month before the first surgery (April 2009) reveals the spinal canal stenosis L4–L5, some epidural lipomatosis (white arrows), and fatty degeneration of the paraspinal muscles (black arrow), but no paraspinal lipoma is visible. (A) Sagittal T2. (B) Sagittal T1. (C) Axial T2, level L4–L5. (Courtesy of Dr. Karin Nüssle-Kügele, Ulm, Germany.)
Fig. 3 Swelling in the scar area (November 2012).
diameter > 10 cm (perhaps already > 3 cm according to Bidault et al9), < 75% fatty tissue, presence of septa with swirling aspect, nodular areas, and nonadipose mass. Of these criteria, the visible septa with some swirling aspect (►Fig. 4)
Klessinger et al.
and the size > 3 cm were the only suspect features in our case. However, because there was no contrast enhancement and the typical interspersion of muscle fibers and adipose mass, it was decided to treat the tumor as being probably benign. The peculiarity of this case is the size and the localization of the lipoma in the lumbar paraspinal musculature and the well-documented rapid growth following surgery. Lipomas occurring in deep locations or those having unusual features may be confused with liposarcoma.10 The mechanisms of their infiltrative growth are not fully understood.3 The growth of the lipoma in this case was clearly infiltrative. The bigger part of the tumor was found subfascially, the other part subcutaneously, with clear margins and the aspect of a capsule on MRI. The origin of the tumor remained unclear. Because of the infiltrative growth and the presence of muscular tissue in the histopathologic specimen, the lesion was classified as a deep-seated muscular lipoma. Typically, even intramuscular lipomas do not exhibit atypical features.3 Sometimes the infiltration of the tumor can be seen and lipocytes are admixed to skeletal muscle fibers in various ratios,3 like in our case (►Fig. 5). Microscopically, an intramuscular lipoma is composed of mature lipocytes, the same as in lipomas found in other areas. Macroscopically,
Fig. 4 Magnetic resonance imaging 1 year after the second operation (laminectomy and complete removal of the lipoma) was performed (November 2012). An even bigger recurrent lipoma has now grown (white arrows) and reaches ventrally into the spinal canal. Dorsally, the lipoma reaches the subcutis and is responsible for the skin swelling (Fig. 3). The space-occupying lesion is clearly demarcated on the sagittal images and has a capsule but no perifocal edema. It exhibits hyperintense fatty signal intensity in T1- and T2-weighted images and is hypointense after fat saturation; however, there is no clear-cut border to the paraspinal muscles on axial images, with muscle fibers clearly extending into the lipomatous tissue. There is no relevant contrast enhancement. Striate areas of higher signal intensity after contrast medium application (black arrows) are due to muscle parenchyma and septa. (A) Sagittal T2. (B) Sagittal T1. (C) Axial T2, level L5. (D) Sagittal short tau inversion recovery. (E) Sagittal T1 (fat saturated) with contrast medium. (F) Axial T1 (fat saturated) with contrast medium. Journal of Neurological Surgery—Part A
Downloaded by: Washington University. Copyrighted material.
Recurrent Intramuscular Lipoma
Recurrent Intramuscular Lipoma
Klessinger et al. after herniorrhaphy, a revision operation revealed a large lipoma of the spermatic cord.16 However, a lipoma of the spermatic cord is a common condition of the male population,17 whereas a lipoma in the lumbar paraspinal musculature is so far unknown. To the best of our knowledge, this is the first report of such a condition. The peculiarity of this report lies in the growth, size, and recurrence of a lipoma that developed in the postoperative period. The factors that may have influenced its growth remain unclear.
Conclusion
Fig. 5 (A) Histologic confirmation of the intramuscular lipoma with numerous well-differentiated mature adipocytes within the skeletal muscle tissue in a representative tissue section covering the lipoma and parts of the bordering skeletal muscle. (B, C) Even within the groups of large number adipocytes resembling the pattern of mature adipose tissue, small bundles of skeletal muscle fibers were observed (black arrows). (C) At the high-power level the skeletal muscle fibers were identified morphologically by the sarcoplasm-associated localization of the nuclei. Calibration bar in (C) corresponds to (A) 5,000 µm, (B) 1,000 µm, and (C) 100 µm.
intramuscular lipomas are not always as well circumscribed as the superficial type.3 Therefore, intramuscular recurrence is common.11–14 The rapid growth of the lipoma, however—in this case within a year—remains outstanding. The mechanisms for increased growth tendency of such lipomas are still under debate.1,15 Multiple theories have been suggested as an underlying cause that provoke the uncontrolled growth of giant cell lipomas,1 involving the role of endocrine, dysmetabolic, and genetic factors. Most authors propose microtrauma or muscle damage that causes rupture of the fibrous septa and anchorage connections between the skin and deep fascia, thus allowing the adipose tissue to proliferate.1,3,15 Fat cell overgrowth due to muscular damage is not uncommon and has been reported in several orthopedic diseases such as muscular dystrophy and rheumatoid arthritis, as well as in other joint diseases and various neuropathies.3 Although dorsal surgery of the lumbar spine certainly always generates muscle injury, it almost never actually results in the rapid growth of a lipoma. An interrelation with the interspinous distraction device cannot be proved. The lipoma started to grow after the implantation of the interspinous distraction device, but the recurrence occurred after the removal of the implant. The medical literature contains only one report about the growth of a lipoma in the postoperative period. Twenty years Journal of Neurological Surgery—Part A
References 1 Lahrach K, el Kadi KI, Mezzani A, Marzouki A, Boutayeb F. An
2
3
4
5
6
7
8
9
10 11
12
13
unusual case of an intramuscular lipoma of the biceps brachii. Pan Afr Med J 2013;15:40 Phalen GS, Kendrick JI, Rodriguez JM. Lipomas of the upper extremity. A series of fifteen tumors in the hand and wrist and six tumors causing nerve compression. Am J Surg 1971;121(3): 298–306 Mori K, Chano T, Matsumoto K, Ishizawa M, Matsusue Y, Okabe H. Type-selective muscular degeneration promotes infiltrative growth of intramuscular lipoma. BMC Musculoskelet Disord 2004;5:20 Tallini G, Dal Cin P, Rhoden KJ, et al. Expression of HMGI-C and HMGI(Y) in ordinary lipoma and atypical lipomatous tumors: immunohistochemical reactivity correlates with karyotypic alterations. Am J Pathol 1997;151(1):37–43 Tkachenko A, Ashar HR, Meloni AM, Sandberg AA, Chada KK. Misexpression of disrupted HMGI architectural factors activates alternative pathways of tumorigenesis. Cancer Res 1997;57(11): 2276–2280 Jones AP, Lewis CJ, Dildey P, Hide G, Ragbir M. Lipoma or liposarcoma? A cautionary case report. J Plast Reconstr Aesthet Surg 2012;65(1):e11–e14 El Ouni F, Jemni H, Trabelsi A, et al. Liposarcoma of the extremities: MR imaging features and their correlation with pathologic data. Orthop Traumatol Surg Res 2010;96(8):876–883 Meyer KA, Bancroft LW, Dietrich TJ, Kransdorf MJ, Peterson JJ. Imaging characteristics of benign, malignant, and infectious jaw lesions: a pictorial review. AJR Am J Roentgenol 2011;197(3): W412–421 Bidault F, Vanel D, Terrier P, et al. Liposarcoma or lipoma: does genetics change classic imaging criteria? Eur J Radiol 2009;72(1): 22–26 Weiss SW. Lipomatous tumors. Monogr Pathol 1996;38:207–239 Uemura T, Suse T, Yokoyama T, Mitsukawa N, Yoshikawa A. Intramuscular benign lipoma of the temporalis muscle. Scand J Plast Reconstr Surg Hand Surg 2002;36(4):231–234 Pélissier A, Sawaf MH, Shabana AH. Infiltrating (intramuscular) benign lipoma of the head and neck. J Oral Maxillofac Surg 1991; 49(11):1231–1236 Mattel SF, Persky MS. Infiltrating lipoma of the sternocleidomastoid muscle. Laryngoscope 1983;93(2):205–207
Downloaded by: Washington University. Copyrighted material.
The rapid growth and recurrence of an intramuscular benign lipoma after decompression of the lumbar spinal canal is a rare cause of pain by compression of the surrounding structures including the neural elements in the spinal canal. The lipoma can reach dimensions that result in a visible and palpable swelling of the skin.
Recurrent Intramuscular Lipoma
Klessinger et al.
16 Vashu R, Subramaniam M. Large lipoma of the spermatic cord
of the head and neck. Case report and literature review. Arch Otolaryngol Head Neck Surg 1986;112(11):1210–1212 15 Allen B, Rader C, Babigian A. Giant lipomas of the upper extremity. Can J Plast Surg 2007;15(3):141–144
presenting as post-operative recurrent hernia in a middle aged gentleman: a case report. Cases J 2009;2:8500 17 Nasr AO, Tormey S, Walsh TN. Lipoma of the cord and round ligament: an overlooked diagnosis? Hernia 2005;9(3):245–247
Downloaded by: Washington University. Copyrighted material.
14 Scherl MP, Som PM, Biller HF, Shah K. Recurrent infiltrating lipoma
Journal of Neurological Surgery—Part A
