Lymphangioleiomyomatosis with superimposed organizing pneumonia diagnosed by transbronchial lung cryobiopsy: A case report.

A 38-year-old woman presented with exertional dyspnea, corresponding to a modified Medical Research Council score of 1 [ 10 ]. Following the detection of multiple infiltrative opacities on chest X-ray, she was referred to our hospital. She had a 0.5 pack-year smoking history (from 25 to 30 years of age) and a history of allergic dermatitis, allergic rhinitis, and endometriosis in her late 20s. Her family history included asthma and hypertension (father) and hypertension (mother). She worked as a dentist. Approximately 1 year prior to presentation, she had been taking vitamins (pyridoxine hydrochloride, riboflavin butyrate, tocopherol acetate, ascorbic acid, and calcium pantothenate) for worsening allergic dermatitis and rhinitis. She had experienced a dry cough for the past 4 months. One month prior to presentation, she had been taking olopatadine hydrochloride and CEDARCURE Japanese cedar pollen sublingual tablets. On clinical grounds of suspected bacterial infection, she was given antibiotics but did not have clinical improvement, and she was subsequently admitted to our hospital. Her peripheral pulse oximetry on ambient air was 96%. Chest auscultation revealed no crackles or wheezes. Laboratory findings were as follows: white blood cells, 11,000/μL (neutrophils, 62.4%; eosinophils, 11.5%; lymphocytes, 20.4%; basophils, 0.4%; monocytes, 5.3%); hemoglobin, 14.2 g/dL; platelets, 56.2 × 10 4 /μL; lactate dehydrogenase, 313 U/L; and C-reactive protein, 15.7 mg/dL. Markers of interstitial pneumonia were as follows: Krebs von den Lungen-6 was normal (152 U/mL; cutoff ≤500 U/mL), while surfactant protein-D was elevated (184.3 ng/mL; cutoffs ≤110 ng/mL). Specific autoantibodies, including antinuclear antibody, were not detected, and no clinical findings suggestive of CTD were observed. Immunoglobulin E was elevated (2317 U/mL). Severe acute respiratory syndrome coronavirus 2 reverse transcription polymerase chain reaction test was negative. Chest X-ray demonstrated alveolar infiltrates mainly in the right upper and left middle lung fields ( Fig. 1 ). High-resolution chest CT revealed alveolar opacities predominantly in the upper lobes of both lungs, along with round, well-defined, thin-walled cysts of relatively uniform size diffusely distributed throughout the lungs ( Fig. 2 ). Pulmonary function testing showed restrictive ventilatory impairment and reduced diffusing capacity (vital capacity % predicted [%VC], 49.8%; forced expiratory volume in 1s/forced vital capacity [FEV 1 %], 84.6%; and diffusing capacity of the lung for carbon monoxide % predicted [%DL CO ], 73.6%). Fig. 1 Chest X-ray showing alveolar infiltrates predominantly in the right upper and left middle lung fields. Fig. 2 High-resolution computed tomography of the chest revealing patchy alveolar opacities predominantly in the upper lobes with ground-glass opacities (A-C), along with diffuse thin-walled cysts in both lungs (D). Chest X-ray showing alveolar infiltrates predominantly in the right upper and left middle lung fields. High-resolution computed tomography of the chest revealing patchy alveolar opacities predominantly in the upper lobes with ground-glass opacities (A-C), along with diffuse thin-walled cysts in both lungs (D). For evaluation of alveolar opacities and multiple cysts, bronchoscopy was performed; however, adequate wedging for bronchoalveolar lavage (BAL) could not be achieved on the right side. Therefore, BAL was performed in the left lingular segment. A total of 150 mL of sterile saline was instilled in three 50-mL aliquots, and 106 mL of fluid was recovered (recovery rate, 71.0%). The total cell count was 3.5 × 10 5  cells/μL. Differential cell counts of BAL fluid showed macrophages 70.3%, lymphocytes 12.2%, neutrophils 2.8%, and eosinophils 14.6%; and a CD4/CD8 ratio of 0.9. No pathogenic organisms were detected. TBLB specimens from the left upper lobe demonstrated intra-alveolar organization without obvious eosinophilic infiltration ( Fig. 3 ). Two additional specimens from the left lower lobe showed no significant findings. Histopathological examination of the TBLB specimen confirmed OP. Given the concern for drug-induced OP, all medications were discontinued for 18 days. However, despite drug withdrawal, the patient showed clinical and radiographic deterioration. Based on these findings, she was diagnosed with COP. Increased serum levels of SP-D without KL-6 elevation observed in this patient was consistent with diagnosis of COP [ 11 ]. She was treated with intravenous high-dose methylprednisolone, 1 g daily for 3 successive days, followed by oral prednisolone (PSL) at 0.6 mg/kg. PSL was tapered, and corticosteroid (CS) therapy was completed after 43 days ( Fig. 4 ). On high-resolution CT performed one month after treatment completion, consolidation in both lung fields had resolved ( Fig. 5 ). All medications remained discontinued. Pulmonary function improved, with %FVC of 94.5% and FEV 1 % of 82.0%. Fig. 3 Transbronchial lung biopsy specimens from the left upper lobe. Polypoid plugs of loose connective tissue occupy alveolar spaces and alveolar ducts on high-power magnification (Hematoxylin-Eosin stain; HE) (A). Elastica van Gieson staining demonstrates intra-alveolar organization (B). Fig. 4 Clinical course of treatment. AZM: Azithromycin Hydrate, LVFX: Levofloxacin, mPSL: methylprednisolone, PSL: prednisolone, CRP: C-reactive protein. Fig. 5 High-resolution computed tomography of the chest. A) At admission (before corticosteroid treatment). B) Two months after completion of corticosteroid treatment. Pulmonary alveolar opacities in both lung fields at admission (A) resolved after corticosteroid treatment (B). Transbronchial lung biopsy specimens from the left upper lobe. Polypoid plugs of loose connective tissue occupy alveolar spaces and alveolar ducts on high-power magnification (Hematoxylin-Eosin stain; HE) (A). Elastica van Gieson staining demonstrates intra-alveolar organization (B). Clinical course of treatment. AZM: Azithromycin Hydrate, LVFX: Levofloxacin, mPSL: methylprednisolone, PSL: prednisolone, CRP: C-reactive protein. High-resolution computed tomography of the chest. A) At admission (before corticosteroid treatment). B) Two months after completion of corticosteroid treatment. Pulmonary alveolar opacities in both lung fields at admission (A) resolved after corticosteroid treatment (B). Although COP had resolved, multiple cystic lung lesions remained undiagnosed ( Fig. 6 ). LAM was suspected based on the high-resolution chest CT findings of diffuse cystic lung disease. No family history of TSC was noted, and she had no history of seizures or cognitive impairment. At the time of COP diagnosis, the serum VEGF-D level was 566.8 pg/mL, although serum levels of VEGF-D >800 pg/mL are considered useful for diagnosing LAM [ 1 , 3 , 12 ]. No LAM cells were identified in TBLB specimens. Abdominal magnetic resonance imaging (MRI) performed during CS therapy showed multiple high-signal nodules on T2-weighted imaging in the para-aortic region, suggestive of LAM ( Fig. 7 ). The patient declined SLB for pathological confirmation. Fig. 6 High-resolution computed tomography of the chest. A) After corticosteroid treatment. B) Approximately two years later. Consolidation in both lung fields disappeared after corticosteroid treatment, leaving diffuse multiple thin-walled cysts of unequal size (A). Partial enlargement of the cystic lesions was observed approximately two years later (B). Fig. 7 Abdominal MRI showing multiple high-signal nodules on T2-weighted imaging in the para-aortic region (circled in red). High-resolution computed tomography of the chest. A) After corticosteroid treatment. B) Approximately two years later. Consolidation in both lung fields disappeared after corticosteroid treatment, leaving diffuse multiple thin-walled cysts of unequal size (A). Partial enlargement of the cystic lesions was observed approximately two years later (B). Abdominal MRI showing multiple high-signal nodules on T2-weighted imaging in the para-aortic region (circled in red). The extent of cystic lesions on CT was evaluated using lung volume percentage with Hounsfield unit (HU) values below −950 [ 13 ]. In this case, the proportion of cystic lesions with values below −950 HU increased from 2.18% before the onset of COP to 3.77% over 2 years after the diagnosis of COP, and the serum VEGF-D level had risen to 1392.9 pg/mL. Pulmonary function testing showed normal values: % FVC, 94.8%; FEV 1 %, 82.4%; %FEV 1 , 92.5%; and %DL CO , 114.2%. According to the proposed diagnostic algorithm for LAM [1, 3), the case could be diagnosed with LAM. However, because the pathological finding of OP was observed on TBLB, the cystic disease in this case could have been associated with CTDs such as Sjögren's syndrome (SS). Therefore, TBLC was performed to obtain a definitive pathological diagnosis, considering the patient's age and the possibility of alternative diagnoses. Under intravenous anesthesia, TBLC was performed using a flexible 1.9-mm cryoprobe (ERBE, Tubingen, Germany), and three specimens were obtained from the right lower lobe (B 8 a, B 8 b, B 9 a), with a freezing time of 6 s for each. Immediately after the cryobiopsy, a Fogarty® balloon catheter (E−080-4F; Edwards Lifesciences, Irvine, USA) was used to occlude the biopsy site. TBLC was completed without complications, such as pneumothorax or bleeding. On TBLC, proliferation of spindle cells with slightly clearer cytoplasm than ordinary smooth muscle cells was observed in the walls of cystic structures on hematoxylin–eosin stain ( Fig. 8 A). Immunohistochemistry demonstrated positivity for estrogen receptor ( Fig. 8 B), α-smooth muscle actin ( Fig. 8 C), and human melanin black 45 ( Fig. 8 D), confirming the diagnosis of LAM. Fig. 8 Transbronchial lung cryobiopsy specimens from the right lower lobe. Proliferation of spindle cells with slightly clearer cytoplasm compared with ordinary smooth muscle cells is seen in the walls of cystic structures (hematoxylin-eosin stain; HE) (A). Immunohistochemistry demonstrates positivity for estrogen receptor (ER) (B), α-smooth muscle actin (SMA) (C), and human melanin black 45 (HMB45) (D), confirming a diagnosis of lymphangioleiomyomatosis. Transbronchial lung cryobiopsy specimens from the right lower lobe. Proliferation of spindle cells with slightly clearer cytoplasm compared with ordinary smooth muscle cells is seen in the walls of cystic structures (hematoxylin-eosin stain; HE) (A). Immunohistochemistry demonstrates positivity for estrogen receptor (ER) (B), α-smooth muscle actin (SMA) (C), and human melanin black 45 (HMB45) (D), confirming a diagnosis of lymphangioleiomyomatosis.

Naoko Takeuchi: Writing – review & editing, Writing – original draft. Takayuki Takimoto: Writing – review & editing. Mitsuhiro Moda: Writing – review & editing. Ryota Shintani: Writing – review & editing. Yukari Kamiyama: Writing – review & editing. Tomoko Kagawa: Writing – review & editing. Hiromitsu Sumikawa: Writing – review & editing. Shigeki Shimizu: Writing – review & editing. Yoshikazu Inoue: Writing – review & editing. Toru Arai: Writing – review & editing, Supervision.

Written informed consent for publication was obtained from the patient described in this article.

Not required for this case report in accordance with institutional policy.

None.

We reported the first case of LAM with concomitant COP, in which a definitive diagnosis of LAM was ultimately established by TBLC.

We encountered a case of LAM with concomitant COP that was ultimately diagnosed by TBLC. To our knowledge, this is the first reported case of LAM with concomitant COP. At referral, high-resolution chest CT demonstrated peripheral-predominant alveolar opacities and multiple lung cysts. TBLB specimens showed pathological features of OP. Secondary OP due to infection, medications, or CTDs was considered [ 9 ]. However, despite antimicrobial therapy and withdrawal of all medications, both the inflammatory response and pulmonary opacities worsened, making these etiologies less likely. Regarding CTDs, autoantibodies were negative, and no clinical findings were suggestive of CTD. Cystic lung diseases, which should be differentiated from LAM, show characteristic radiological features. Birt-Hogg-Dubé syndrome presents thin-walled, round, or elliptical cysts, predominant in the lower zone, often located in paramediastinal, and closely associated with pleura and blood vessels [ 14 , 15 ]. Pulmonary Langerhans cell histiocytosis is characterized by cysts of variable size and shape, ranging from round to bizarre, with upper-lobe predominance and relative sparing of the lung bases; associated nodules and thick-walled cavities may also be present [ 16 ]. LIP and follicular bronchiolitis demonstrate smooth, round, thin-walled cysts of variable size, often with eccentric vessels and internal septations [ 14 ]. Among CTDs, SS is most strongly associated with LIP. SS is an important differential diagnosis for multiple pulmonary cysts [ 17 ]. In the case reported by Martínez-Balzano et al. [ 17 ], a patient with primary SS presented with multiple cysts and bilateral upper-lobe opacities. SLB revealed OP with prominent bronchial lymphocytic infiltration, but no cystic lesions were observed on the biopsy specimens. The patient was treated with PSL for 6 months, which led to resolution of the consolidation, although the multiple cysts persisted [ 17 ]. In our case, SS was not diagnosed at the time of COP diagnosis or 2 years later, and the cysts had slightly enlarged. However, some cases of SS are negative for anti-SS-A and anti-SS-B antibodies, and approximately 16% of patients with SS and concomitant interstitial lung disease initially present with pulmonary symptoms [ 18 , 19 ]. Because CTDs, including SS, have been reported in 3.3% of patients with LAM [ 20 ], ongoing vigilance for their clinical manifestations is warranted. In the present case, both LAM and COP were identified. Although the concomitant of multiple rare lung diseases is possible, the relationship between these two conditions remains unclear. Therefore, the concomitant of LAM and COP in this case may be incidental, and a causal relationship cannot be clearly established. Further accumulation of similar cases may help to clarify any potential association. Vascular endothelial growth factor-D (VEGF-D) is a lymphangiogenic factor that plays a key role in the pathogenesis of LAM [ 1 ]. Serum VEGF-D levels are elevated in patients with LAM and serve as a useful diagnostic biomarker, particularly when levels exceed 800 pg/mL [ 12 , 21 ]. In this case, the VEGF-D level was initially low and subsequently increased during the clinical course. Elevated VEGF-D levels have been reported to be associated with disease severity and clinical manifestations in LAM [ 22 ]. However, it remains unclear whether longitudinal changes in VEGF-D levels directly reflect disease progression. Therefore, the observed increase in this case should be interpreted with caution, particularly in the context of possible concomitant conditions such as COP. Because pulmonary function data prior to the onset of COP are unavailable, we could not evaluate the relationship between disease progression and VEGF-D levels; however, the increase in lung volume below −950 HU may indicate that the elevation in VEGF-D could reflect progression of LAM. Although SLB has traditionally been considered the gold standard for histopathological diagnosis of pulmonary LAM [ 1 , 23 ], TBLB offers the advantage of being less invasive. According to the 2016 and 2017 American Thoracic Society/Japanese Respiratory Society (ATS/JRS) guidelines, in patients with parenchymal cysts characteristic of LAM but without other definitive diagnostic features, TBLB should be performed before SLB if tissue confirmation is required (conditional recommendation, very low certainty of evidence) [ 3 ]. TBLB has been reported to establish a diagnosis of LAM in more than 50% of appropriately selected patients [ 3 ]. In a previous Japanese study of 141 patients with pathologically confirmed LAM, 113 cases (80.1%) were diagnosed by SLB and 18 (12.8%) by TBLB [ 24 ]. More recent Japanese reports demonstrated higher yields with TBLB, with 17 of 24 cases (71%) and 15 of 19 cases (79%) diagnosed using this method [ 12 , 25 ]. TBLB was particularly effective in 76.5% of patients with a %DL CO of 66.4% or lower [ 13 ], and in 83% of patients with cystic lesions occupying more than 25% of total lung volume on chest CT [ 25 ], supporting its utility as a diagnostic tool. However, our case did not meet either criterion, which likely explains why LAM could not be diagnosed by TBLB. Another study reported an overall diagnostic yield of 57.0% (49/86) with TBLB, noting significantly higher rates in patients with three to four biopsy specimens compared with those with only one to two [ 26 ]. These findings suggest that increasing the number of specimens obtained may improve diagnostic accuracy. TBLC is considered valuable in the diagnosis of various interstitial lung diseases because it yields larger specimens than TBLB [ 4 , 27 ]. Several case reports have described LAM diagnosed by TBLC [ [5] , [6] , [7] ]. In one case, pulmonary function was preserved (%FEV 1 81%; %DL CO within normal range), but diffuse prominent cystic lesions were present [ 5 ]. It is possible that this case could have been diagnosed if more TBLB specimens had been obtained. Another report described two patients with relatively preserved pulmonary function (case 1: %FEV 1 113.6%, %DL CO 95.9%; case 2: %FEV 1 108.2%, %DL CO 72.9%) who had early-stage lung lesions similar to those in our patient [ 6 ]. These findings suggest that diagnosing LAM may be more challenging with TBLB than with TBLC, particularly in patients with minimal interstitial involvement. In studies evaluating diagnostic methods for LAM, the degree of cyst formation on HRCT was classified as minimal (60%) [ 28 ]. Among patients with minimal cyst formation, LAM was diagnosed more frequently by TBLC (5/19, 26.3%) and SLB (11/39, 28.2%) than by TBLB (3/61, 4.9%) [ 28 ]. The distribution of cyst formation severity was similar between TBLC-LAM-positive and SLB-LAM-positive patients. Pulmonary function was also compared across biopsy methods. Although %FEV1 and %DL CO did not differ significantly between groups, TBLB-LAM-positive patients (median %FEV 1 58.5%) had significantly lower %FEV 1 than that in SLB-LAM-positive patients (median %FEV 1 76.6%; p = 0.03), while values were not significantly different from those of TBLC-LAM-positive patients (median %FEV 1 70.4%) [ 28 ]. These findings suggest that in patients with minimal cyst formation, TBLB has limited diagnostic utility, whereas TBLC and SLB achieve comparable diagnostic yields regardless of cyst burden. In the same study, TBLC-related complications in LAM patients included pneumothorax in 3.3% (1/30), minor bleeding in 26.7% (8/30), and moderate bleeding in 3.3% (1/30); no severe bleeding or other adverse events were reported [ 28 ]. Similarly, in an analysis of 402 biopsy procedures in lung transplant recipients, the incidence of pneumothorax and bleeding was comparable between TBLC and TBLB [ 29 ]. In addition, several case reports of LAM diagnosed by TBLC described no procedure-related complications [ [5] , [6] , [7] ]. In our case, TBLB did not yield a diagnosis when OP was identified, whereas TBLC subsequently provided a definitive diagnosis of LAM, thereby avoiding SLB. The procedure was completed safely without complications, supporting TBLC as a potential diagnostic option in suspected early-stage LAM.

Lymphangioleiomyomatosis (LAM) is a slowly progressing systemic neoplastic disease characterized by the proliferation of smooth muscle-like tumor cells (LAM cells) that form multiple cysts in the lungs [ 1 ]. It typically presents with rounded, thin-walled cysts that are uniformly distributed within otherwise normal lung parenchyma on high-resolution chest computed tomography (CT) [ 1 , 2 ]. The differential diagnosis includes other cystic lung diseases such as emphysema, Birt-Hogg-Dubé syndrome, lymphoid interstitial pneumonia (LIP), pulmonary Langerhans cell histiocytosis, amyloidosis, and light-chain deposition disease [ 1 ]. A minimally invasive diagnostic approach is preferred for confirming LAM [ 3 ]. For individuals with parenchymal cysts characteristic of LAM on chest high-resolution CT but lacking definitive features such as a diagnosis of tuberous sclerosis complex (TSC), an angiomyolipoma, elevated serum vascular endothelial growth factor-D (VEGF-D) (≥800 pg/mL), a chylous effusion, or a lymphangioleiomyoma, a transbronchial lung biopsy (TBLB) is recommended before considering surgical lung biopsy (SLB) [ 1 , 3 ]. Transbronchial lung cryobiopsy (TBLC) is widely used for the diagnosis of diffuse lung diseases. Compared with TBLB, TBLC can obtain larger tissue samples, and the specimens are less likely to be affected by crush [ 4 ]. In recent years, scattered reports have described the diagnosis of LAM by TBLC [ 1 , [5] , [6] , [7] ], but no clear consensus has been reached regarding its role in establishing the diagnosis. Cryptogenic organizing pneumonia (COP) is histopathologically characterized by intraluminal plugs of loose connective tissue within alveolar spaces and alveolar ducts, which may also extend into bronchioles [ 8 ]. COP has no identifiable cause and is classified as a subtype of idiopathic interstitial pneumonia, whereas secondary organizing pneumonia (OP) can result from infections, drug reactions, connective tissue diseases (CTDs), or other conditions. On high-resolution CT, the predominant radiologic pattern is peripheral, multifocal consolidation [ 9 ]. To date, no reports have described LAM with concomitant COP. We present a case of LAM that was initially undiagnosed by TBLB during the workup of COP but was definitively diagnosed by TBLC.

YI has received research grants from The Japanese Ministry of Health, Labour, and Welfare, consulting fees from Boehringer Ingelheim, Roche, Shionogi, Taiho, Kyorin pharmaceutical, Tanabe Mitsubishi, CSL Behring, Vicore Pharma AB, AbbVie, Avalyn Pharma, Savara, and lecture fees from Boehringer Ingelheim, Shionogi, Kyorin pharmaceutical, NobelPharma, GSK, Astra Zeneca, Yunglin Pharma. TA has received lecture fees from Nobelpharma. All other authors declare no conflicts of interest.