lymphangiomyomatosis ( lam ) is a rare disease of a hamartomatous nature characterized by proliferation of abnormal lymphatic smooth muscle cells . smooth muscle cells are often classified in the family of perivascular epithelioid cells ( pec ) . some of these cells include renal angiomyolipoma , sugar tumor of the lung and pancreas , and clear - cell myomelanocytic tumor of the falciform ligament . the primary site of origin is the lung and occurrence is usually associated with decreased pulmonary function and chylous effusions ( 2 ) . the outcome of this disease can be devastating but the underlying etiology and effective treatments are unknown . extrapulmonary lam is quite rare and mainly located in the pelvis and retroperitoneum , along the lymphatic channels . the clinical features are the presence of chylous ascites , a palpable abdominal mass , and abdominal pain ( 3 ) . we report a case of a young female who was initially diagnosed with retroperitoneal lam that eventually led to pulmonary involvement with decreased lung function . a 21-yr - old female patient presented with a sudden onset of low abdominal pain . with the clinical impression of an ovarian cyst , she was transferred from a local gyn clinic to our hospital . gynecologic ultrasonography revealed a large posterior pelvic mass with an irregular echogenicity measuring 9.74.2 cm in size ( fig . 1 ) . the patient had no specific past medical history with a parity of 0 - 0 - 0 - 0 . pelviscopy showed a large , thin walled , partly cystic , pelvic mass measuring approximately 10 cm in diameter . the mass was adherent to the internal and external iliac vessels and the right pelvic wall . the retroperitoneal mass was partly removed by pelviscopy and samples were submitted for frozen section analysis . the submitted specimen for frozen section analysis consisted of multiple irregular fragments of soft tissue weighing approximately 30 g. the tumor was soft and grayish - tan with focal areas of hemorrhage ( fig . 2 ) . on frozen section , the possibility of epithelioid smooth muscle tumor or paraganglioma was suspected . microscopically , the masses were characterized by a haphazard proliferation of smooth muscle cells ( lam cells ) arranged in fascicular , trabecular , and papillary patterns around a ramifying network of endothelium - lined spaces . the cells were plump or epithelioid with abundant eosinophilic cytoplasm and bland nuclei with no mitotic activity . aggregations of lymphocytes were between the lam cells , representing vestiges of preexisting lymph nodes ( fig . most of the lam cells showed a positive reaction for alphasmooth muscle actin ( dako co. , carpinteria , ca , u.s.a . ) , vimentin ( zymed , san francisco , ca , u.s.a . ) , desmin ( bio - genex , san ramon , ca , u.s.a . ) , and hmb-45 ( dako ) ( fig . seoul , korea ) , cytokeratin ( dako ) , chromogranin ( zymed ) , and cd 34 ( immunotec , marseille , cedex , france ) were negative . newcastle , u.k . ) receptors were observed in only 10% of the lam cells . after operation , the patient had continuous oozing of chylous ascitic fluid of approximately 1,500 to 2,000 ml per day . there was no clinical or radiological evidence of pulmonary involvement at the time of the initial diagnosis . chest ct scans showed diffuse , small , thin walled cystic lesions in both lung parenchymas with pleural effusion ( fig . the patient was treated with tamoxifen and medroxyprogesterone , but the response was limited . even after chest tube insertion and pleurodesis , she continued to drain approximately 800 to 2,300 ml of chylous fluid per day . in the terminal stages of the disease , the patient suffered severe respiratory distress and died six months after initial operation . the submitted specimen for frozen section analysis consisted of multiple irregular fragments of soft tissue weighing approximately 30 g. the tumor was soft and grayish - tan with focal areas of hemorrhage ( fig . 2 ) . on frozen section , the possibility of epithelioid smooth muscle tumor or paraganglioma was suspected . microscopically , the masses were characterized by a haphazard proliferation of smooth muscle cells ( lam cells ) arranged in fascicular , trabecular , and papillary patterns around a ramifying network of endothelium - lined spaces . the cells were plump or epithelioid with abundant eosinophilic cytoplasm and bland nuclei with no mitotic activity . aggregations of lymphocytes were between the lam cells , representing vestiges of preexisting lymph nodes ( fig . most of the lam cells showed a positive reaction for alphasmooth muscle actin ( dako co. , carpinteria , ca , u.s.a . ) , vimentin ( zymed , san francisco , ca , u.s.a . ) , desmin ( bio - genex , san ramon , ca , u.s.a . ) , and hmb-45 ( dako ) ( fig . 5 ) . seoul , korea ) , cytokeratin ( dako ) , chromogranin ( zymed ) , and cd 34 ( immunotec , marseille , cedex , france ) were negative . newcastle , u.k . ) receptors were observed in only 10% of the lam cells . after operation , the patient had continuous oozing of chylous ascitic fluid of approximately 1,500 to 2,000 ml per day . there was no clinical or radiological evidence of pulmonary involvement at the time of the initial diagnosis . chest ct scans showed diffuse , small , thin walled cystic lesions in both lung parenchymas with pleural effusion ( fig . the patient was treated with tamoxifen and medroxyprogesterone , but the response was limited . even after chest tube insertion and pleurodesis , she continued to drain approximately 800 to 2,300 ml of chylous fluid per day . in the terminal stages of the disease , the patient suffered severe respiratory distress and died six months after initial operation . zamboni et al . ( 1 ) described a group comprising sugar tumor , angiomyolipoma , and lymphangiomyoma as a special family of tumors . the nature of perivascular proliferation of abnormal smooth muscle cells and common antigenic expression of hmb-45 , a melanosomal antigen , leads to the concept of so - called perivascular epitheloid cells - pecoma . positive cells are found in both lam and angiomyolipoma ; however , angiomyolipomas are characterized by the presence of abundant adipose tissue and by disorganized components of blood vessels ( 4 ) . the incidence of angiomyolipomas in patients with lam has been reported to be as high as 60% ( 2 ) . matsui et al . ( 3 ) regarded angiomyolipomas as an unusual but distinct expression of the proliferative capacity of lam cells . lam is a tumor of the lymphatic channels and lymph nodes clinically manifested by recurrent chylous pleural effusions and ascites . lam of the lungs is characterized microscopically by abnormal smooth muscle proliferation causing gradual obstruction of small airways , lymphatics , and vasculature ( 5 ) . the typical presenting symptoms include dyspnea ( 83% ) and pneumothorax ( 69% ) ( 2 ) . ( 6 ) reviewed 32 extrapulmonary lam cases , including 22 cases of extrapulmonary lam reported by matsui et al . ( 3 ) . among the reported cases of clinically significant extrapulmonary lam , 14 cases occurred in the lower retroperitoneum or pelvic cavity ( 3 , 4 , 6 ) . most extrapulmonary lam lesions occurred in lymph nodes along the lymphatic vessels of the posterior mediastinum , retroperitoneum , and the pelvic cavity . the diagnosis of extrapulmonary lam preceded that of pulmonary lam in 13 of 17 patients for whom follow - up data were available ( 3 ) . in this case , extrapulmonary manifestations preceded chylous pleural effusion . in korea , approximately 24 cases of lam have been reported in the current literature , all with a primary site in the lungs ( 7 - 9 ) . this case is , to our knowledge , the first extrapulmonary lam reported in korea . the origin and cause of this disease are yet to be undetermined however there are some common peculiar aspects . lam can be divided into a sporadic form , as in this case , or a tuberous sclerosis - associated form ( 10 - 12 ) . there have been many studies regarding the genetic predisposition of lam , especially associated with the mutation of tuberous sclerosis genes ( tsc1 and tsc2 ) ( 12 , 13 ) . tsc is an autosomal dominant disorder and is manifested as seizures , mental retardation , autism , and hamartomatous tumors of the brain , heart , kidney , lung , and skin . these tumors include cerebral cortical tumors , subependymal giant cell astrocytomas , retinal hamartomas , cardiac rhabdomyomas , renal angiomyolipomas , and facial angiofibromas ( 13 ) . four of the 32 extrapulmonary lam cases were associated with tuberous sclerosis ( 6 ) . the speculation that lam is a female sex hormone dependent tumor is supported by the high prevalence rate in women of reproductive age and exacerbation of the disease by pregnancy or by administration of estrogen . numerous studies and case reports regarding clinical trials of hormonal therapy had been reported ( 14 , 15 ) . however , the role of estrogen and progesterone receptors in proliferation of smooth muscle and the therapeutic efficacy of hormone therapy are not well established . our patient was treated with tamoxifen and medroxyprogesterone , but her response was limited . despite a variety of treatment regimens developed since the first description of lam , patient survival has not improved appreciably . lam progresses slowly and most patients die within 10 yr of diagnosis ( 16 ) . despite the slow progression rate of other lam cases , our patient died of the disease six months after operation prolonged chylous peritoneal and pleural effusions , aggressive deterioration of pulmonary function , and her lack of response to various treatment modalities were major contributing factor .
lymphangioleiomyomatosis ( lam ) is a rare disease usually occurring in young women of child - bearing age . 
 it is characterized by a distinctive proliferation of lymphatic smooth muscle cells , especially occurring in the pulmonary parenchyme . 
 the majority of primary lam occurs in the lung , but there are a few reports of extrapulmonary cases . 
 we report a case of a 21-yr - old female who first complained of low abdominal pain and was referred from a local clinic with the impression of an ovarian cyst . 
 gynecologic ultrasonography revealed a large posterior pelvic mass with an irregular echogenicity measuring 9.74.2 cm in size . 
 pelviscopy showed a large , thin walled , partly cystic , pelvic mass . 
 the mass was partly removed . 
 microscopically , the mass was characterized by a haphazard proliferation of smooth muscle cells arranged in fascicular , trabecular , and papillary patterns around a ramifying network of endothelium - lined spaces . 
 the cells were plump or epithelioid with abundant eosinophilic cytoplasm and showed a positive reaction for both alpha - smooth muscle actin and hmb-45 antigen . 
 surgical and pathological findings were consistent with pelvic retroperitoneal lam . despite the numerous treatment attempts , the patient suffered from intractable chylous ascites and developed pulmonary lam and died due to severe respiratory distress .