Conclusions
Liposarcoma is one of the most common soft tissue sarcomas, and represents 20% of mesenchymal malignancies. It tends to occur in the retroperitoneum and deep soft tissues of the trunk and extremities in adults[
2,
3]. It is unlike lipoma and relatively rare in the fat-rich areas such as the subcutaneous tissue, intestinal tract, and mesocolon[
3]. Historically, liposarcoma has been divided into five subtypes according to the World Health Organization: well differentiated, dedifferentiated, myxoid, pleomorphic, and mixed type[
4].
Liposarcomas rarely involve the gastrointestinal tract[
5‐
16], and a primary liposarcoma of the colon is extremely uncommon. A recent textbook on gastrointestinal pathology cites no cases of colonic liposarcoma[
17], and to the best of our knowledge, only nine cases of primary liposarcoma of the colon have been reported worldwide[
5‐
13]. However, mixed-type primary liposarcoma of the colon has never been reported. Mixed-type liposarcoma is defined as a tumor that demonstrates the morphological features of myxoid, pleomorphic, and/or well differentiated/dedifferentiated liposarcoma[
4]. This subset accounts for approximately 4% of all liposarcomas and mostly develops in the abdomen.
Clinical features of primary liposarcoma of colon are variable and nonspecific: abdominal pain, diarrhea, weight loss, anemia, and hematochezia, constipation and sometimes, an abdominal mass may be palpable (Table
1)[
5‐
13]. However, no reports have described primary liposarcoma of the colon presenting as hemoperitoneum; in our case, hemoperitoneum may be caused by the necrosis which was progressed by overgrowing tumor. Most of the published cases are of large tumors that ranged in greatest dimension from 6 to 12 cm (in our case, the tumor size was 20 cm, but it might have been enlarged by internal bleeding), and these are common among liposarcomas in general[
3]. Most interesting thing in present case is that other types of liposarcoma were found simultaneously in colon and retroperitoneum; the retroperitoneal liposarcoma was well differentiated type, and colonic one was mixed type. In the operative field, the retroperitoneal liposarcoma was found after removal of the colon and it appeared that the tumors were separate with no apparent contact.
Table 1
Review of reported cases of primary liposarcoma of the colon.
Wood et al. | 62/F | Pain and palpable mass | ICV | 7.5 × 12 | MX | Died 2 yrs |
Parks et al. | 54/F | Abdominal discomfort, diarrhea, anemia, and weight loss | AC | 6 × 4 | PM | NA |
Magro et al. | 65/F | Pain and intussusception | Cecum | 5 | WD | Alive 6 mo |
Chen | 52/F | Pain and hematochezia | DC | 7.5 × 5 | WD | Alive 2 yrs |
Gutsu et al. | 46/M | Pain and palpable mass | AC | 12 × 11 | MX | Alive 1 yr |
Shahidzadeh et al. | 56/F | Hematochezia | AC | 3.5 × 2.8 | WD | NA |
Chaudhary et al. | 66/F | Pain, hematochezia, weight loss, and palpable mass | DC | 6 × 3 | WD | Alive 6 mo |
Jaboui et al. | 69/M | Pain, constipation, and weight loss | DC | 7 × 6 | DD | Alive 10 mo |
D'Annibale et al. | 79/F | Pain, constipation, and weight loss | AC | 5 × 5.2 | PM | Died 2.5 yrs |
Current case | 41/M | Pain and palpable mass | AC | 20 × 13 | Mixed | Alive 2 yrs |
Most studies have treated primary liposarcoma of the colon with complete wide excision[
5‐
13]; in our case, right hemicolectomy was performed for complete remove of colon liposarcoma and all gross retroperitoneal mass was excised widely. A treatment protocol has not been established because of the small number of reported cases. The effects of chemotherapy for liposarcoma has not been yet unknown[
18], but radiotherapy has shown to affect survival rates[
19]. The patient was discussed with a medical oncologist and no adjuvant therapy was recommended but it was suggested that regular clinical follow up every 6 months was needed.
The prognosis of primary liposarcoma of the colon is not known. In the first case reported by Wood and Morgenstern[
5], tumor recurrence developed 3 years after surgery for myxoid colon liposarcoma. Some factors have been accepted as indicators of poor prognosis: age >45 years, presence of round cells, necrotic areas within the mass[
3], and dissemination of the disease[
12]. Although our patient had necrotic areas within the mass, and the tumor could be disseminated due to ruptured hemoperitoneum, he is still alive after 24 months without any recurrence.
The present case is extremely rare because it is mixed type, presenting as hemoperitoneum and was combined with a different histological type of retroperitoneal liposarcoma. No standardized guidelines have been established for its treatment because too small a number of cases have been reported, but surgical resection was considered the treatment of choice in our case. A larger number of cases will be necessary to determine whether additional treatment such as chemotherapy and radiotherapy is necessary or effective in liposarcoma of colon.
Competing interests
The authors declare that they have no competing interests.
Authors' contributions
YYC participated in data collection and conceived the design. SYJ, pathologist, assembled pathologic data and reviewed pathology. YJK is the operating surgeon, collected data and participated in critical review. All authors read and approved the final manuscript.