Full-Endoscopic Foraminal Decompression for Foraminal Stenosis Following Osteoporotic Vertebral Fracture in an Elderly Woman Under Local Anesthesia:A Case Report.

Osteoporotic vertebral fracture (OVF) is common in the elderly population. In this report, we describe a case with radiculopathy due to foraminal stenosis caused by OVF in a very elderly patient that was treated successfully by full-endoscopic foraminotomy under local anesthesia. The patient was an 89-year-old woman who presented with a chief complaint of left leg pain for 5 years. She visited a couple of hospitals and finally consulted us to determine the exact cause of the pain. Computed tomography scans were obtained and selective nerve root block at L3 was performed. The diagnosis was radiculopathy at L3 due to foraminal stenosis following OVF. The patient had severe heart disease, so we decided to avoid surgery under general anesthesia and planned full-endoscopic spine surgery under local anesthesia. We performed transforaminal full-endoscopic lumbar foraminotomy at L3-L4 to decompress the L3 nerve root. The leg pain disappeared completely immediately after surgery. Postoperative computed tomography confirmed appropriate bone resection. The leg pain did not recur during a year of postoperative follow-up. OVF may cause lumbar radiculopathy as a result of foraminal stenosis, and transforaminal full-endoscopic lumbar foraminotomy under local anesthesia would be the best option in an elderly patient with poor general condition. J. Med. Invest. 71 : 179-183, February, 2024.

Mismatch between Augmented Reality Navigation Images and Actual Location of a Cauda Equina Tumor:A Case Report.

BACKGROUND: Augmented reality navigation is the one of the navigation technologies that allows computer-generated virtual images to be projected onto a real-world environment. Augmented reality navigation can be used in spinal tumor surgery. However, it is unknown if there are any pitfalls when using this technique. CASE PRESENTATION: The patient in this report underwent complete resection of a cauda equina tumor at the L2-L3 level using microscope-based augmented reality navigation. Although the registration error of navigation was <1 mm, we found a discrepancy between the augmented reality navigation images and the actual location of the tumor, which we have called "navigation mismatch". This mismatch, which was caused by the mobility of the spinal tumor in the dura mater, seems to be one of the pitfalls of augmented reality navigation for spinal tumors. CONCLUSIONS: Combined use of intraoperative ultrasound and augmented reality navigation seems advisable in such cases. J. Med. Invest. 71 : 174-176, February, 2024.

Viral entry and translation in brain endothelia provoke influenza-associated encephalopathy.

Influenza-associated encephalopathy (IAE) is extremely acute in onset, with high lethality and morbidity within a few days, while the direct pathogenesis by influenza virus in this acute phase in the brain is largely unknown. Here we show that influenza virus enters into the cerebral endothelium and thereby induces IAE. Three-weeks-old young mice were inoculated with influenza A virus (IAV). Physical and neurological scores were recorded and temporal-spatial analyses of histopathology and viral studies were performed up to 72 h post inoculation. Histopathological examinations were also performed using IAE human autopsy brains. Viral infection, proliferation and pathogenesis were analyzed in cell lines of endothelium and astrocyte. The effects of anti-influenza viral drugs were tested in the cell lines and animal models. Upon intravenous inoculation of IAV in mice, the mice developed encephalopathy with brain edema and pathological lesions represented by micro bleeding and injured astrocytic process (clasmatodendrosis) within 72 h. Histologically, massive deposits of viral nucleoprotein were observed as early as 24 h post infection in the brain endothelial cells of mouse models and the IAE patients. IAV inoculated endothelial cell lines showed deposition of viral proteins and provoked cell death, while IAV scarcely amplified. Inhibition of viral transcription and translation suppressed the endothelial cell death and the lethality of mouse models. These data suggest that the onset of encephalopathy should be induced by cerebral endothelial infection with IAV. Thus, IAV entry into the endothelium, and transcription and/or translation of viral RNA, but not viral proliferation, should be the key pathogenesis of IAE.

Impact of Tumor Grade Distribution on Genetic Alterations in Clear Cell Renal Cell Carcinoma and Prostate Cancer.

BACKGROUND/AIM: A genomic analysis based on next-generation sequencing is important for deciding cancer treatment strategies. Cancer tissue sometimes displays intratumor heterogeneity and a pathologic specimen may contain more than two tumor grades. Although tumor grades are very important for the cancer prognosis, the impact of higher tumor grade distribution in a specimen used for a genomic analysis is unknown. PATIENTS AND METHODS: We retrospectively analyzed the data of 61 clear cell carcinoma and 46 prostate cancer patients that were diagnosed between December 2018 and August 2022 using the GeneRead Human Comprehensive Cancer Panel or SureSelect PrePool custom Tier2. Genome annotation and curation were performed using the GenomeJack software. RESULTS: Tumor mutation burden (TMB) was increased in proportion to the higher tumor grade distribution in grade 2 clear cell renal cell carcinoma (ccRCC). In PC, Grade Group 3/4 specimens that included an increased distribution of Gleason pattern 4 had more frequent gene mutations. CONCLUSION: Our results suggest the importance of selecting the maximum distribution of higher tumor grade areas to obtain results on the precise gene alterations for genomics-focused treatments.

Return-to-play outcomes after full-endoscopic spine surgery under local anesthesia in professional baseball players: Comparison by timing of surgery.

BACKGROUND: Full-endoscopic spine surgery via a transforaminal approach (TF-FESS) is minimally invasive and could help athletes quickly return to play. When treating professional athletes, we have to consider their season schedule. In this study, we investigated the characteristics of Japanese professional baseball players who underwent TF-FESS and examine how the timing of surgery influenced their postoperative course. METHODS: Ten players who underwent TF-FESS (discectomy, foraminoplasty, or thermal annuloplasty according to their diagnosis) under local anesthesia were analyzed. Multilevel surgeries were performed at the same time in patients with lesions at multiple levels. The patients were divided into three groups according to timing of surgery (pre/during/post-season). Time to complete return to play and duration of official game loss were compared between the three groups. RESULTS: All players (100 %) could return to their original level of professional play after FESS surgery. Seven of the 10 patients underwent two-level surgery. The mean time until complete return to play was 4.6 months (range, 2-8 months) and the mean duration of game loss was 1.5 months (range, 0-4 months). The mean duration of game loss was shorter in the post-season group than in the other groups (0.9 vs 2,4 months), and 4 of 6 patients in the post-season group did not miss any games. CONCLUSIONS: TF-FESS is a good technique for achieving a quick return to play in professional baseball players. In particular, surgery performed during the post-season could allow players to return to play after adequate rehabilitation with no game loss.

Differentiating Between Epstein-Barr Virus-positive Lymphoid Neoplasm Relapse and Post-transplant Lymphoproliferative Disorder After Sex-mismatched Hematopoietic Stem Cell Transplantation.

After allogeneic hematopoietic stem cell transplantation (HSCT), accurate differentiation between donor-derived post-transplant lymphoproliferative disorder (PTLD) and relapse of recipient-derived lymphoproliferative disorder (LPD) is crucial for determining treatment. Conventional diagnostic approaches for PTLD include histopathological examination, flow cytometry, and chimerism analysis of bulk tumor tissue. However, these methods are inconclusive in cases in which the primary disease is an Epstein-Barr virus (EBV)-positive LPD and is of the same lineage as that of the post-HSCT LPD tumor cells. Particularly, in cases where the number of tumor cells in the tissue is low, it is difficult to determine the origin of tumor cells. In this study, we developed a new method to simultaneously detect signals using sex chromosome fluorescence in situ hybridization, immunofluorescence staining, and EBV-encoded small RNA in situ hybridization on a single section of formalin-fixed paraffin-embedded histopathological specimen. The utility of the method was validated using specimens from 6 cases of EBV-positive LPD after sex-mismatched HSCT that were previously difficult to diagnose, including Hodgkin lymphoma-like PTLD that developed after HSCT for Hodgkin lymphoma and recurrence of chronic active EBV infection. This method successfully preserved the histologic structure after staining and allowed accurate determination of tumor cell origin and lineage at the single-cell level, providing a definitive diagnosis in all cases. This method provides a powerful tool for the diagnosis of LPDs after sex-mismatched HSCT.

Morphological Evaluation of Lumbar Facet Joints in Professional Baseball Players.

Background: Many professional baseball players experience low back pain, a major cause of which is lumbar facet joint arthropathy. Purpose: To evaluate the relationship between the dominant hand side and facet joint morphology in baseball movement. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Participants were 25 Japanese professional baseball players (11 pitchers and 14 fielders) with low back pain and lower limb symptoms. Player age, hand dominance, and length of professional playing experience were recorded, and the lateral diameter of all lumbar facet joints was determined from the axial computed tomography scans. We defined the facet joints ipsilateral and contralateral to the dominant hand as dominant and nondominant, respectively. The nondominant-to-dominant (N/D) ratio of the lateral diameter was calculated, and differences between the pitchers and fielders were analyzed using the unpaired t test. Results: The average player age and length of professional playing experience were 26.9 years (range, 19-37 years) and 7.2 years (range, 1-15 years), respectively. The right hand was dominant in 9 pitchers and 5 fielders, while the left hand was dominant in 2 pitchers and 9 fielders. In pitchers, the average lateral facet joint diameter on the nondominant side was significantly larger than on the dominant side at all vertebral levels except L1 to L2 (P < .05 for all). The N/D ratio for each facet joint was 1.06 (L1-L2), 1.11 (L2-L3), 1.10 (L3-L4), 1.12 (L4-L5), and 1.12 (L5-S1). In fielders, the average lateral facet joint diameter on the dominant side was significantly larger than on the nondominant side at L3 to L4 (P < .05), with N/D ratios of 0.98 (L1-L2), 0.96 (L2-L3), 0.94 (L3-L4), 0.97 (L4-L5), and 0.98 (L5-S1). The N/D ratio was significantly larger in pitchers than in fielders at all levels (P < .05 for all). Conclusion: The facet joints of professional baseball players were enlarged asymmetrically, with different tendencies observed between pitchers and fielders. Although pitching and batting are movements that transmit the rotation from the lower limbs to the upper limbs, the effects of rotation and lateral flexion were associated significantly with facet joint hypertrophy.

Relationship between duration of atrial fibrillation and right heart structure remodeling as assessed by 3-dimensional transesophageal echocardiography.

BACKGROUND: Tricuspid valve (TV) remodeling occurs in patients with atrial fibrillation (AF); however, the affecting factor related to TV remodeling in AF remains to be elucidated. We sought to explore whether the AF persistence itself affects right heart remodeling. METHODS: A total of 372 lone AF patients (234 paroxysmal AF [paroxAF] and 138 persistent AF [persAF]) who underwent 3-dimensional transesophageal echocardiography (3D-TEE) was retrospectively reviewed. The duration from first-detected episode of AF to the TEE exam date was defined as AF duration. RESULTS: PersAF patients had a larger TV area index (625.4 vs 719.0 mm2/m2; P < 0.001) and a higher right atrium area-to-right ventricle end-systolic area ratio (RA/RVESA ratio, 1.7 vs 1.9; P = 0.005) than paroxAF patients. The prevalence of AF-tricuspid regurgitation was higher in persAF than in paroxAF patients (1.3% vs 12.3%; P < 0.001). In persAF patients, AF duration was moderately correlated with TV diameter and 3D-TEE-derived TV annular area but not in paroxAF. On multivariable analysis, AF duration was independently associated with TV annular dilatation even after adjustment for RA/RVESA ratio and tricuspid regurgitation severity (ß 0.37 [95% CI: 0.77-1.81]; P < 0.001). Additionally, AF duration with cutoff values of 20 months for predicting TV annular dilatation and 37 months for predicting RA/RVESA ratio > 2.1 had both high diagnostic accuracies among persAF patients (both P < 0.01). CONCLUSIONS: AF duration itself is independently associated with right heart remodeling in persAF but not in paroxAF, such as TV annular dilatation and predominant RA remodeling which may lead to subsequent TR progression and adverse outcomes.

Doublet or Triplet Antiemetic Prophylaxis for Nausea and Vomiting Induced by Trastuzumab Deruxtecan: an Open-Label, Randomized, and Multicenter Exploratory Phase 2 Study.

Background: Trastuzumab deruxtecan is classified as an anticancer agent that poses a moderate emetic risk in the international guidelines for antiemetic therapy. The guidelines recommend emesis prophylaxis using a two-drug combination therapy comprising a 5-hydroxytryptamine-3 receptor antagonist (5-HT3RA) and dexamethasone (DEX). However, the high incidence of nausea and vomiting associated with trastuzumab deruxtecan is problematic. The National Comprehensive Cancer Network guideline version 1.2023 classified trastuzumab deruxtecan as having a high risk of emesis and changed its recommendation to a triplet regimen including a neurokinin-1 receptor antagonist (NK1RA). However, the emetogenic potential of trastuzumab-deruxtecan and the optimal antiemetic prophylaxis are controversial. Hence, this exploratory phase 2 study aimed to assess the efficacy and safety of treatment comprising 5-HT3RA and DEX with or without a NK1RA in preventing trastuzumab deruxtecan-induced nausea and vomiting. Methods: We conducted an open-label and randomized exploratory phase 2 study at 14 centers in Japan. Patients with breast cancer who were scheduled to receive trastuzumab deruxtecan were enrolled in this study. The patients were randomly assigned to receive granisetron and DEX (arm GD) or granisetron, DEX, and aprepitant (fosaprepitant; arm GDA). The primary endpoint was complete response (CR; no emesis or no rescue therapy) during the overall phase (120 h after the start of trastuzumab deruxtecan). Results: Between September 2020 and March 2023, 40 patients were randomly assigned to the GD (n = 19) or GDA (n = 21) arm. In the GDA arm, one patient who did not complete the use of the rescue medication listed in the diary was excluded from the efficacy analysis, which included the use of rescue medication. The CR rates during the overall phase were 36.8% and 70.0% in the GD and GDA arms, respectively (odds ratio 0.1334; 95% confidence interval [CI]: 0.0232-0.7672; P = 0.0190), with a difference of 33.2%. No grade 3 or 4 toxicity related to antiemetic therapy was observed. Conclusions: Patients receiving trastuzumab deruxtecan require triple therapy, including mandatory NK1RA administration.

Absolute measurement of sampling jitter in audio equipment.

This study proposes a method for analyzing sampling jitter in audio equipment based on the time-domain analysis, considering the temporal fluctuations of the zero-crossing points in the recorded sinusoidal waves to characterize the jitter. This method enabled the separate evaluation of jitter in an audio player from those in audio recorders when the same playback signal is simultaneously fed into two audio recorders. The experiments were conducted using commercially available portable devices with a maximum sampling rate of 192 000 samples per second. The results demonstrated that jitter values on the order of a few tens of picoseconds can be identified in an audio player. Moreover, the proposed method enabled the separation of jitter from phase-independent noise utilizing the left and right channels of the audio equipment. As such, this method is applicable for performance evaluation of audio equipment, signal generators, and clock sources.

Advantages of Full-endoscopic Trans-Kambin's Triangle Lumbar Interbody Fusion for Degenerative Spondylolisthesis: Illustrative Cases.

Various approaches to lumbar interbody fusion have been described. The usefulness of full-endoscopic trans-Kambin's triangle lumbar interbody fusion has recently been reported. This technique has several advantages in patients with degenerative spondylolisthesis, including the ability to improve symptoms without decompression surgery. Moreover, given that the entire procedure is performed percutaneously, it can be performed without increasing the operation time or surgical invasiveness, even in obese patients. In this article, we discuss these advantages and illustrate them with representative cases.

Urinary Retention Suggesting Aseptic Meningitis: Meningitis-Retention Syndrome Without Physical Signs of Meningeal Irritation.

Meningitis-retention syndrome (MRS) is the combination of aseptic meningitis and acute urinary retention that occurs in the absence of other neurological diseases. The cause(s) of MRS remain unclear. A 57-year-old Japanese woman was referred to our hospital for the evaluation of persistent fever and headache. The fever's cause was initially unclear, but the presence of urinary retention raised concern about possible aseptic meningitis despite no physical indications of meningeal irritation. Only typical cases of MRS have been reported thus far to our knowledge, and it is important that clinicians are aware of MRS when it presents in this atypical form.

Blue light induces apoptosis and autophagy by promoting ROS-mediated mitochondrial dysfunction in synovial sarcoma.

BACKGROUND: Synovial sarcoma (SS) has limited treatment options and there is an urgent need to develop a novel therapeutic strategy to treat SS. Blue light (BL) has been shown to inhibit the growth of several cancer cells. However, the efficacy of BL in soft tissue sarcomas such as SS has not been demonstrated, and the detailed mechanism underlying the antitumor activity of BL is not fully understood. In this study, we investigated the antitumor effect of BL on SS. METHODS: Human SS cell lines were continuously irradiated with BL using light-emitting diodes (LEDs) in an incubator for in vitro analysis. The chicken chorioallantoic membrane (CAM) tumors and xenograft tumors in mice were subjected to daily BL irradiation with LEDs. RESULTS: BL caused growth inhibition of SS cells and histological changes in CAM tumors. BL also suppressed the migration and invasion abilities of SS cells. The type of cell death in SS cells was revealed to be apoptosis. Furthermore, BL induced excessive production of reactive oxygen species (ROS) in mitochondria, resulting in oxidative stress and malfunctioned mitochondria. Reducing the production of ROS using N-acetylcysteine (NAC), a ROS scavenger, attenuated the inhibitory effect of BL on SS cells and mitochondrial dysfunction. In addition, BL induced autophagy, which was suppressed by the administration of NAC. The autophagy inhibitor of 3-methyladenine and small interfering RNA against the autophagy marker light chain 3B facilitated apoptotic cell death. Moreover, BL suppressed tumor growth in a mouse xenograft model. CONCLUSION: Taken together, our results revealed that BL induced apoptosis via the ROS-mitochondrial signaling pathway, and autophagy was activated in response to the production of ROS, which protected SS cells from apoptosis. Therefore, BL is a promising candidate for the development of an antitumor therapeutic strategy targeting SS.

Neoadjuvant chemotherapy using nanoparticle albumin-bound paclitaxel plus trastuzumab and pertuzumab followed by epirubicin and cyclophosphamide for operable HER2-positive primary breast cancer: a multicenter phase II clinical trial (PerSeUS-BC04).

BACKGROUND: Nanoparticle albumin-bound paclitaxel (nab-PTX) is a promising antibody partner for anti-human epidermal growth factor receptor 2 (HER2). We performed neoadjuvant chemotherapy (NAC) for HER2-positive breast cancer (BC) using nab-PTX plus trastuzumab (T-mab) and pertuzumab (P-mab), followed by epirubicin and cyclophosphamide (EC). METHODS: In this multicenter phase II clinical trial (January 2019-July 2020), patients with stage I (T1c)-IIIB HER2-positive primary BC were treated with four cycles of nab-PTX plus T-mab and P-mab, followed by four cycles of EC. The primary endpoint was the pathological complete response (pCR) rate. Secondary endpoints were clinical response rate (RR), adverse events (AE), and tumor-infiltrating lymphocytes (TILs) in biopsy samples. RESULTS: In total, 43 patients were enrolled (mean age, 54 years). Twenty-two patients had HER2, and 21 patients had luminal/HER2-subtypes. The overall pCR rate was 53.5% (23/43, 95% CI: 42.6-64.1%, p = 0.184), whilst the pCR for HER2 was 68.2% (15/22, 95% CI: 45.1-86.1) and 38.1% for luminal/HER2 (8/21, 95% CI: 18.1-61.6%). The RR was 100% [clinical (c) CR:25, partial response (PR): 18]. AEs (≥ G3) included neutropenia (23.3%), leukopenia (7.0%), liver dysfunction (7.0%), and peripheral neuropathy (4.7%) when nab-PTX was administered. EC administration resulted in leukopenia (34.2%), neutropenia (31.6%), and febrile neutropenia (15.8%). The TILs in preoperative biopsy samples were significantly higher in pCR compared to non-pCR samples. CONCLUSION: Nab-PTX plus T-mab and P-mab induced a high pCR rate in HER2-positive BC, particularly in the HER2-subtype. Given that AEs are acceptable, this regimen is safe and acceptable as NAC for HER2-positive BC.

History of malignant neoplasia lessens oocyte developmental competence: a case-control study.

OBJECTIVE: We investigated how history of malignant neoplasia affected oocyte developmental competence. METHODS: Fifty-two cycles of assisted reproductive technology (ART) in women with a history of malignant disease (case group) were compared with fifty-two matched cycles of ART in women with no cancer history (control group). Propensity score matching involving age and body mass index was used to select controls. Oocyte developmental competence and rates of pregnancy and livebirth were compared as main outcomes. To investigate whether the cancer itself had affected oocyte developmental competence, this outcome variable was compared between case cycles with and without cancer surgical histories. RESULTS: Numbers of fertilized oocytes (FO), cleaving embryos (CE), and superior CE (SCE) were significantly lower in cases than controls. Rates of fertilization and of development to SCE from retrieved oocytes (RO), FO, or CE also were lower in cases than controls (63, 25, 39, and 43% vs. 72, 36, 50, and 55%, respectively). Cases had significantly lower rates of clinical pregnancy and livebirth per embryo transfer than controls (7.6 and 1.5% vs. 20.4 and 14.0%). Rates of development to SCE from RO, FO, and CE showed no significance for differences between cases with and without cancer operations (22, 37, and 40% vs. 31, 42, and 49%). CONCLUSIONS: A woman's history of malignant neoplasia was associated with decreased oocyte developmental competence, possibly related to patient's background factors predisposing to tumor.

A Report of a Case With Pediatric Ovarian Steroid Cell Tumor, Not Otherwise Specified, Found With Precocious Puberty.

A 4-year-old girl was admitted to our hospital because of precocious puberty. Radiologic findings revealed a fist-sized solid tumor in the left ovary without ascites, peritoneal dissemination, and distant metastasis. The patient underwent left salpingo-oophorectomy without spillage. The size of the excised tumor was 10.0×9.0×4.8 cm. On pathologic examination, the tumor was diagnosed as an ovarian steroid cell tumor, not otherwise specified. In the present case, although the diameter of the tumor (>7 cm) and three mitoses per 10 high-power fields represented some potential for malignancy, we opted for careful observation without chemotherapy as the tumor was of clinical stage Ia.

A fatal case of hemophagocytic lymphohistiocytosis associated with gestational psittacosis without symptoms of pneumonia.

Psittacosis is a zoonotic infection caused by Chlamydia psittaci. Most patients present with acute respiratory symptoms and systemic illness. When C. psittaci infects pregnant women, it causes severe clinical manifestations called gestational psittacosis. Here we report a case of gestational psittacosis. Our patient lacked respiratory symptoms, and pathological postmortem examinations revealed severe placentitis. Both DNA and immunohistochemical analyses were positive for C. psittaci from formalin-fixed paraffin-embedded tissues. The chlamydial DNA in the placenta was about 100 times more abundant than that in the lungs; therefore, the placenta rather than the lungs was the probable target of the C. psittaci infection during this pregnancy. We could not identify the source of infection. Gestational psittacosis should be considered in the differential diagnosis for fever of unknown origin during pregnancy, even in cases lacking respiratory symptoms.

Music Roles Affect the Selection of Consumption Means: A Questionnaire Survey of People's Expectations for Music and Exploratory Factor Analysis.

People listen to music for various purposes, and the roles that listeners expect from music can vary from person to person. In recent years, "subscription-based streaming services" (hereinafter referred to as "subscription") have increased their share in the music market, thereby changing the way people listen to music. Though, the impact of this change on the role of music, is yet to be explored. This study analyzed survey data to reveal the relationship between the expected roles of music and the choice of music consumption means, including subscription. In particular, we obtained that a factor in the use of subscription is the expectation of constructing a personal identity. We also found that both purchase and live usage are affected by two factors: the expectation of fan identity construction and the expectation of artist contribution. This indicates that subscription is not an alternative to the existing means, but a new kind of consumption means in the music market. It was also found that subscription facilitates the construction of personal identity through music. Supplementary Information: The online version contains supplementary material available at 10.1007/s12626-022-00115-x.

Histological analysis of testes in patients with 5 alpha-reductase deficiency type 2: Comparison with cryptorchid testes in patients without endocrinological abnormalities and a review of the literature.

As evidenced by the intact histology of the testes during infancy, testicular differentiation during the prenatal period occurs normally in individuals with 5 alpha-reductase type 2 deficiency (5αRD); however, a majority of these individuals suffer from azoospermia or oligospermia during adulthood, indicating that impaired spermatogenesis occurs postnatally. Although the accompanying cryptorchidism may be partly responsible for this process, the underlying mechanisms remain largely unknown. To address this issue, we retrospectively compared the histological findings of descended testes in a 3-mo-old patient and undescended testes in an 18-yr-old patient with 5αRD. In the latter, testicular histology was compared to that of cryptorchid testes obtained from five adolescent patients without endocrinological abnormalities. Histological findings of a 3-mo-old patient revealed normal number of germ cells with intact seminiferous tubules. In contrast, an 18-yr-old patient showed marked reduction in germ cell number and atrophic seminiferous tubules. The findings were very similar to those observed in cryptorchid testes without endocrinological abnormalities. These findings suggest that the decrease in germ cells in 5αRD patients may be at least partly caused by accompanying cryptorchidism. As the number of germ cells did not decrease during the infantile period, early orchiopexy is recommended to prevent a decrease in germ cell number and preserve fertility.