Characteristics and Treatment Strategies for Basicervical and Transcervical Shear Fractures of the Femoral Neck.

This study aimed to define basicervical and transcervical shear fractures using area classification and to determine the optimal osteosynthesis implants for them. The clinical outcomes of 1042 proximal femur fractures were investigated. A model of the proximal femur of a healthy adult was created from computed tomography images, and basicervical and transcervical shear fractures were established in the model. Osteosynthesis models were created using a short femoral nail with a single lag screw or two lag screws and a long femoral nail with a single lag screw or two lag screws. The minimum principal strains of the fracture surfaces were compared when the maximum loads during walking were applied to these models using finite element analysis software. Basicervical fractures accounted for 0.96% of all proximal femur fractures, 67% of which were treated with osteosynthesis; the failure rate was 0%. Transcervical shear fractures accounted for 9.6% of all proximal femur fractures, 24% of which were treated with osteosynthesis; the failure rate was 13%. Finite element analysis showed that transcervical shear fracture has high instability. To perform osteosynthesis, multiple screw insertions into the femoral head and careful postoperative management are required; joint replacement should be considered to achieve early mobility.

Occurrence and clinical outcome of lateral wall fractures in proximal femoral fractures whose fracture line runs from femoral basal neck to subtrochanteric area.

Treatment methods for proximal femoral fractures, when the fractures run from the femoral basal neck to the subtrochanteric area, have not yet been fully reported. Thus, we aimed to clarify osteosynthesis methods based on the fracture frequency and clinical results. We classified the proximal femoral fractures using the Area classification method based on the location (area) of the fracture line. The proximal femur has 4 areas with 3 boundaries; the center of the femoral neck, the boundary between femoral neck and trochanter, and the plane connecting the lower ends of the greater trochanter and the lesser trochanter. Fractures occurring only in Area-1 (proximal from the center of the femoral neck) were classified as Type 1; those in both Areas 1 and 2 (base of the femoral neck) were classified as Type 1-2. Therefore, fractures running from femoral basal neck to the subtrochanteric area were classified as Type 2-3-4. We targeted 60 Type 2-3-4 cases (average age 81 years, 10 men, 50 women) out of 1042 proximal femoral fracture cases who visited 8 hospitals in 2 years. We investigated the presence or absence of lateral trochanteric wall fractures, the selection of internal fixator, and the proportion of poor results. The lateral trochanteric wall fracture was observed in 48% of subjects. Long nails were selected to treat 46% cases, and nails with 2 or 3 proximal lag screws were used in 58% cases. Long nails and those with 2 or 3 lag screws were also used in 59% and 69% of lateral trochanteric wall fractures. Poor results such as cutout or excessive telescoping of lag screw occurred in 11.7% of cases and 17.2% of lateral trochanteric wall fractures. Even in cases where long nails and multiple lag screws were used for femoral trochanteric fractures whose fracture line ran from the femoral basal neck to subtrochanteric area were used, the failure rate was high in the presence of a lateral wall fracture. Therefore, it is necessary to consider careful post-operative treatment for proximal femoral fractures with lateral wall fracture, whose fracture line runs from femoral basal neck to subtrochanteric area.

Rapidly Destructive Coxopathy With Femoral Head Fracture That Is Similar to a Slipped Capital Femoral Epiphysis in an Elderly Woman: A Case Report.

Slipped capital femoral epiphysis (SCFE) generally occurs in adolescents but rarely in adults. Rapidly destructive coxopathy (RDC) is characterized by rapid joint destruction, including disruption of the joint at the femoral head and acetabulum as well as reduction of the joint space, within six to 12 months. The mechanism of RDC is likely multifactorial but has not yet been identified. Moreover, there are no reports of displaced femoral head fractures similar to an SCFE associated with RDC. We report a rare case of RDC with femoral head fracture that is similar to SCFE in an 86-year-old woman. Although the exact cause of the femoral head fracture is unknown, it can develop into RDC. Awareness of orthopedic surgeons regarding this condition is crucial for appropriate treatment, by monitoring the presentation of symptoms and imaging/radiographic findings.

Preoperative medications is one of the factor affecting patient-reported outcomes after total hip arthroplasty.

Although the reported clinical outcomes of total hip arthroplasty (THA) for hip osteoarthritis are satisfactory, not all patients are completely satisfied. Thus, there is interest in predicting postoperative satisfaction before surgery. The influence of comorbidities and preoperative medications on the incidence of complications and duration of hospitalization following THA has become apparent. However, studies about the associations of preoperative medication with clinical outcomes of THA are limited. Therefore, this study aimed to clarify the relationship between preoperative medications and postoperative patient-reported outcomes. This retrospective cross-sectional multicenter study enrolled post-THA patients (79 patients, 90 hips) who were examined from February to March 2019 in eight general hospitals. Outcome measures included patient-reported outcome as Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire (JHEQ) score. Preoperative medications were investigated from medical records. Medications were categorized, and analgesics were categorized into non-steroidal anti-inflammatory drugs (NSAIDs), acetaminophen, pregabalin, duloxetine, neurotropin (an extract from inflammatory rabbit skin inoculated by vaccinia virus), and opioid. To identify the factors associated with JHEQ score, the patients were divided into lower (<55 score) and higher (≥55) JHEQ score groups. Spearman rank correlation coefficient (r) showed significant difference between the total number of preoperative medications and postoperative JHEQ movement subscale (r = -0.37, p < 0.01), mental subscale (r = -0.29, p < 0.01), and JHEQ (r = -0.30, p < 0.01) scores. In the multiple logistic regression analysis, only the total number of preoperative medications was identified as a risk factor for lower JHEQ score (p < 0.01). This study clarified an inverse correlation between the total preoperative medication count and postoperative outcomes and found that larger total count of preoperative medications is a risk factor of poor postoperative patient-reported outcomes of THA.

Initial Rotational Instability of the Tapered Wedge-Shaped Type Cementless Stem.

BACKGROUND: Because the tapered wedge-shaped type cementless stem has a small anteroposterior width and a low occupation rate in the medullary space, postoperative rotational instability and stem subsidence due to inadequate proximal fixation are concerns. The purpose of this study was to clarify the relationship between the rotational instability of the tapered wedge-shaped type cementless stem and femoral canal shape. METHODS: A total of 61 primary total hip arthroplasties with the tapered wedge-shaped type cementless stem Accolade® TMZF (11 males, 50 females; mean age 60 years) from January 2012 to June 2015 who underwent computed tomography before surgery and within 4 weeks and 1 year after surgery were evaluated. The preoperative femoral neck anteversion angle, preoperative femoral canal flair index, the degree of postoperative stem subsidence within 1 year after operation, and the degree of rotational change in the stem setting angle within 1 year after operation were investigated. RESULTS: The mean preoperative femoral neck anteversion angle was 32.2° ± 17.8° (0°-69°), and the mean preoperative canal flair index was 3.68 ± 0.58 (2.44-5.55). There were no stem subsidence cases within 1 year after operation. The mean degree of rotational change in the stem from immediately to 1 year after surgery was -0.4° ± 1.7° (-3°-3°). There was no significant correlation between the canal flair index and the rotational change in the stem. In addition, the mean difference between the preoperative femoral neck anteversion angle and the stem rotational angle immediately after surgery was only 1.3° ± 5.3° (-29°-15°). CONCLUSIONS: In all cases, including stove-pipe cases, the degree of rotational change in the Accolade® TMZF stem from immediately to 1 year after surgery was within 3°. In other words, regardless of femoral canal shape, the tapered wedge-shaped type cementless stem has little initial rotational instability.

The Differences in Imaging Findings Between Painless and Painful Osteoarthritis of the Hip.

PURPOSE: In osteoarthritis of the hip, the pain may be strong even if the deformity is mild, but the pain may be mild even if the deformity is severe. If the factors related to the pain can be identified on imaging, reducing such factors can alleviate the pain, and effective measures can be taken for cases where surgery cannot be performed. In addition, imaging findings related to the pain are also important information for determining the procedures and the timing of surgery. Thus, the purpose of this study was to identify the differences in features of osteoarthritis seen on imaging between painless and painful osteoarthritis of the hip. METHODS: The subjects were the patients with hip osteoarthritis who visited our department in 2015 and who underwent x-ray, computed tomography (CT), and magnetic resonance imaging (MRI), a total of 29 patients (54 hip joints; mean age 63 years; 8 males and 21 females). The degree of osteoarthritis was determined using the Tönnis grade from the x-ray image. The cartilage morphology, intensity changes of bone marrow on MRI (subchondral bone marrow lesions [BMLs]), osteophytes, joint effusions, and paralabral cysts were scored based on the Hip Osteoarthritis MRI Scoring System (HOAMS). The cross-sectional area of the psoas major muscle at the level of the iliac crest was measured on CT, and the psoas index (PI; the cross-sectional area ratio of the psoas major muscle to the lumbar 4/5 intervertebral disc) was calculated to correct for the difference in physique. Then, the relationships between these and visual analog scale (VAS) scores of pains were evaluated. RESULTS: The average VAS was 55.4 ± 39 mm. The PI and all items of HOAMS correlated with the VAS. The average VAS of Tönnis grade 3 osteoarthritis was 75.8 ± 26 mm. When investigating only Tönnis grade 3 osteoarthritis, the differences between cases with less than average pain and those with above average pain were the BML score in the central-inferior femoral head (P = .0213), the osteophyte score of the inferomedial femoral head (P = .0325), and the PI (P = .0292). CONCLUSION: Investigation of the differences between painless and painful osteoarthritis of the hip showed that the cases with more pain have BMLs of the femoral head on MRI that extend not only to the loading area, but also to the central-inferior area. Even with the same x-ray findings, the pain was stronger in patients with severe psoas atrophy. Thus, the instability due to muscle atrophy may also play a role in the pain of hip osteoarthritis.

A Comparison of the Incidences of Venous Thromboembolism after Total Hip Arthroplasty between the Direct Anterior Approach and the Direct Lateral Approach, Especially in the Early Period after Introduction of the Direct Anterior Approach.

OBJECTIVE: To compare the incidence of venous thromboembolism (VTE) after total hip arthroplasty (THA) using the direct anterior approach (DAA) with that using the direct lateral approach (DLA). In addition, patient background characteristics and the incidence of VTE were compared between the first half and the latter half of the period after introducing DAA and against DLA. METHOD: This was a retrospective, multicenter study involving 109 patients (116 hips) who had undergone primary unilateral THA. Thirty-six hips underwent THA using DAA and 80 hips underwent THA using DLA. Patient information including sex, age, and preoperative diagnosis was collected. The incidence of VTE was compared between DAA and DLA. Moreover, the patients who underwent THA using DAA were divided into 2 groups (first half and latter half groups), and sex, age, body mass index (BMI), and surgical time were compared between the 2 groups. Moreover, the incidence of VTE was compared among the 3 groups (first half of DAA, latter half of DAA, and DLA). RESULTS: The incidence of VTE in the DAA group was significantly higher than that in the DLA group (p=0.014). The incidence of VTE in the first half group was significantly higher than in the latter half group and the DLA group (p=0.035 and p=0.001, respectively), and there was no difference in the incidence of VTE between the latter half group and the DLA group (p=0.923). Surgical time was significantly longer in the first half group than in the latter half group (p=0.046). CONCLUSIONS: In the first half of the period after introducing the DAA, more VTEs occurred than in the DLA. It may be important to shorten the surgical time in the early stage of introducing the DAA, and aggressive anticoagulation therapy may be required until the surgeon becomes familiar with the procedure.

The location of the fracture determines the better solution, osteosynthesis or revision, in periprosthetic femoral fractures.

PURPOSE: Periprosthetic femoral fractures are difficult to treat, but few reports have included many periprosthetic femoral fractures. The purpose of this study was to investigate the trends and characteristics of a large number of periprosthetic femoral fractures and to determine the best treatment strategy for such fractures. METHODS: The fracture type according to the Vancouver classification, the stem fixation style of previous surgery, the elapsed time from previous surgery, and the treatment method for periprosthetic fractures of 51 patients with periprosthetic femoral fractures who were seen between 2006 and 2018 were investigated. RESULTS: The types of fractures according to the Vancouver classification were: type A 5.9%, type B1 47%, type B2 20%, type B3 2.0%, and type C 25%. Of the previous surgeries, 76% were cementless fixation, and 24% were cemented fixation. The mean duration from previous surgery to periprosthetic femoral fracture was 8 years and 7 months (1-358 months), and injury within 1 year from previous surgery was most commonly observed (24%). As treatment for periprosthetic femoral fractures, conservative treatment was performed in 8%, and surgery was performed in 92%. Of the surgery cases, 53% underwent osteosynthesis, and 39% underwent revision surgery. Of type B1 surgery cases, 58% were treated with osteosynthesis, and 33% underwent revision surgery, although type B1 had no stem loosening. CONCLUSION: Many periprosthetic femoral fractures occurred within 1 year after the previous surgery. Therefore, preventive measures for periprosthetic femoral fractures should be started immediately after total hip replacement. In addition, revision surgery was performed even if the stem was not loosened in cases where it was judged that sufficient osteosynthesis could not be performed.

Incidence and Clinical Outcomes of Hip Fractures Involving Both the Subcapital Area and the Trochanteric or Subtrochanteric Area.

PURPOSE: Proximal femoral fractures involving both the subcapital area and the trochanteric or subtrochanteric area have rarely been reported, but they are not uncommon. However, few studies have reported the incidence or clinical outcomes of such fractures. This study investigated such fractures. METHODS: In area classification, the proximal femur is divided into 4 areas by 3 boundary planes: the first plane is the center of femoral neck; the second plane is the border between femoral neck and femoral trochanter; and the third plane links the inferior borders of greater and lesser trochanters. A fracture only in the first area is classified as a Type 1 fracture; one in the first and second areas is classified as a Type 1-2 fracture. Therefore, proximal femoral fractures involving both the subcapital area and the trochanteric area are classified as Type 1-2-3, and those involving both the subcapital area and the subtrochanteric area are classified as Type 1-2-3-4. In this study, a total of 1042 femoral proximal fractures were classified by area classification, and the treatment methods and the failure rates were investigated only for Types 1-2-3 and 1-2-3-4 cases. The failure rate was defined as the incidence of internal fixator cut-out or telescoping >10 mm. RESULTS: Types 1-2-3 and 1-2-3-4 fractures accounted for 1.72%. Surgical treatment was performed for 89%. Of these, 56% underwent osteosynthesis, but the failure rate was 33%. The other patients (44%) underwent prosthetic replacement. Fracture lines of all these fractures were present along trochanteric fossa to intertrochanteric fossa in posterior aspect and just below the femoral head in anterior aspect. CONCLUSION: Fracture involving the subcapital area to the trochanteric or subtrochanteric area was found in approximately 2%. In patients for whom prosthetic replacement was selected, good results were obtained. However, 1/3 of patients who underwent osteosynthesis had poor results.

Two Cases of Periprosthetic Atypical Femoral Fractures in Patients on Long-Term Bisphosphonate Treatment.

The current definition of atypical femoral fractures (AFFs) excludes periprosthetic fractures. However, a few cases of bisphosphonates (BPs) -associated periprosthetic atypical femoral fractures (PAFFs) have been reported in the literature. Here, we report two rare cases of PAFFs that fulfilled the major criteria for AFFs in patients with prolonged use of BPs. Both cases progressed to a complete fracture with minor trauma from an incomplete fracture at the distal tip of the well-fixed femoral stem. The femoral stem effect on lateral femoral cortical bone, together with the decreased bone elastic resistance induced by BPs, was considered the cause of onset. In each case, we performed open reduction and internal fixation using a locking plate with cable grip and postoperatively prescribed teriparatide and low-intensity pulsed ultrasound (LIPUS). Both cases had a good clinical course. However, as conservative treatment was not effective in these cases, treatment such as non-weight-bearing exercises during hospitalization or prophylactic surgery may be necessary. Further studies are needed to determine the optimal treatment strategy.

Comparison of Atypical and Osteoporotic Femoral Shaft Fractures in the Elderly: A Multicenter Study.

BACKGROUND: In atypical femoral fractures, owing to the high rates of complications and delayed healing that accompany the plate fixation, the most favorable treatment is intramedullary nailing. Although there is insufficient evidence, plate fixation is chosen due to anterolateral bowing of the femur. This study compared the bone healing time and rates of complications in atypical femoral shaft fractures and osteoporotic femoral shaft fractures. METHODS: We searched the medical records of 3 institutions in Japan for patients with femoral shaft fractures who visited between 1 January 2010 and 31 December 2015. We identified 65 patients and excluded 37 among these due to high-energy injuries or being younger than 65 years. Among the remaining patients, we identified 17 and 11 women with atypical (AFF group) and osteoporotic femoral shaft fractures (OP group), respectively. RESULTS: In surgical method, there were differences in intramedullary nailing (94.1% versus 27.2%) (p < 0.01). The mean bone healing time was 11.1 months versus 6.7 months in 2 groups (p < 0.01). Iatrogenic femoral fractures during intramedullary nail insertion were observed in both groups, and reoperation was only seen in atypical femoral fractures treated with a plate fixation, but there was no difference in the rate of complications (23.5% versus 9.1%). CONCLUSIONS: In the atypical femoral fracture group, intramedullary nailing was more chosen, but the bone healing time was delayed and plate fixation cases needed reoperation. There was no significant difference in the rate of complications between the 2 groups.

Relationship between clinical results of total hip replacement and postoperative activities including weeding and snow shovelling.

INTRODUCTION: Weeding or snow shovelling is indispensable for life in farm villages of northern countries. Clarifying the relationships between the degrees of these activities after total hip replacement (THR) and the clinical results of THR may enable us to predict the results of THR for high-level activity patients. The relationships between work activities after THR and the results were investigated. METHODS: The subjects were 95 post-THR patients, who consulted 6 hospitals in August 2012. First, the Japanese Orthopaedic Association Hip-Disease Evaluation Questionnaire (JHEQ) and a questionnaire on postoperative activity were administered. Then, the Japanese Orthopaedic Association hip score (JOA score) was evaluated. RESULTS: The subjects' average age was 68 years. The average period after surgery was 4 years and 5 months. Weeding and snow shovelling were performed after THR in 44.2% and 40.0% of cases, respectively. The rate of farming after surgery (25.6%) was greater than that of swimming (21.1%). Both the JOA score and JHEQ were higher in those who played sports after THR than in those who did not (p = 0.003, p = 0.0046). The JOA score of those who performed work activities after THR was higher than that of those who did not (p = 0.0295). CONCLUSIONS: Nearly half of patients performed weeding or snow shovelling after THR, and about 1/4 of the patients engaged in farming after THR. The clinical results in cases doing sports and work activities after THR were better than those of cases not doing such activities. Therefore, these activities may be positively recommended.

A Case of Fracture-Redislocation of the Hip Caused by a Depressed Fracture of the Femoral Head Similar to a Hill-Sachs Lesion.

The present case shows a case of fracture-redislocation of the hip caused by a depressed fracture of the femoral head similar to a Hill-Sachs lesion. A 59-year-old man fell from a roof and his left hip joint was dislocated posteriorly. He was admitted to a nearby hospital, and he was referred to our hospital more than 24 hours after injury. Computed tomography (CT) suggested a bone chip from the posterior wall of the acetabulum roof and a depressed femoral head that cut into the posterior margin of the acetabulum roof. Immediate manual repositioning was performed under general anesthesia on the same day. He left our hospital to go home on day 26 after repositioning, but his left hip joint was dislocated again when he went down the stairs. It was thought that this patient's redislocation occurred due to a femoral head depressed fracture involving the same mechanism as the Hill-Sachs injury seen with dislocation of the shoulder. The remplissage method for the Hill-Sachs injury is difficult for the femoral head. Therefore, total hip replacement was performed, and the patient's postoperative course was good. We conclude that total hip arthroplasty should be considered as one of the best treatment methods for such cases.

The choice of internal fixator for fractures around the femoral trochanter depends on area classification.

PURPOSE: In femoral trochanteric fractures, fractures whose fracture lines extend to the basal neck or to the subtrochanteric part have high instability. Area classification can identify such instable fractures. The best choices of internal fixators for femoral trochanteric fractures were investigated according to area classification. METHODS: Femoral trochanteric fractures were investigated with respect to area classification. In area classification, the proximal femur is divided into 4 areas with 3 boundary lines: Line-1 is the center of the neck; Line-2 is the border between the neck and the trochanteric zone; and Line-3 links the inferior borders of the greater and lesser trochanters. A fracture in only the third area was classified as type 3; one in the second and third areas was classified as type 2-3. RESULTS: Of 284 femoral trochanteric fractures, 50.0 % were type 3, 21 % were type 2-3, 22 % were type 3-4, and 7.4 % were type 2-3-4. Cases with cut-out or excessive telescoping of the internal fixator were defined as the Failure-group; 5.3 % of type 3 and 10.9 % of type 2-3 were in the Failure-group only when short femoral nails with a single rag screw were used. On the other hand, there were no Failure-group cases of type 2-3 with double rag screws. Only 1 case involved a long nail for type 3, while a long nail was used in about half of type 3-4 cases (Chi square test: P < 0.0001). CONCLUSIONS: A double rag screw should be considered for type 2-3. A long nail should be considered for type 3-4.

The reliability of classifications of proximal femoral fractures with 3-dimensional computed tomography: the new concept of comprehensive classification.

The reliability of proximal femoral fracture classifications using 3DCT was evaluated, and a comprehensive "area classification" was developed. Eleven orthopedists (5-26 years from graduation) classified 27 proximal femoral fractures at one hospital from June 2013 to July 2014 based on preoperative images. Various classifications were compared to "area classification." In "area classification," the proximal femur is divided into 4 areas with 3 boundary lines: Line-1 is the center of the neck, Line-2 is the border between the neck and the trochanteric zone, and Line-3 links the inferior borders of the greater and lesser trochanters. A fracture only in the first area was classified as a pure first area fracture; one in the first and second area was classified as a 1-2 type fracture. In the same way, fractures were classified as pure 2, 3-4, 1-2-3, and so on. "Area classification" reliability was highest when orthopedists with varying experience classified proximal femoral fractures using 3DCT. Other classifications cannot classify proximal femoral fractures if they exceed each classification's particular zones. However, fractures that exceed the target zones are "dangerous" fractures. "Area classification" can classify such fractures, and it is therefore useful for selecting osteosynthesis methods.

Simultaneous dislocation of radiocapitellar and distal radioulnar joint.

A 45-year-old male presented to the emergency room of our institution complaining of severe pain around the left elbow. While playing volleyball, he slipped down with his left arm hit between the floor and his body. He complaind of strong pain from left elbow to hand, and active motion of elbow and wrist joint was impossible. His forearm was held in supinated position. On X-ray examination, radius head was deviated to anterior lateral side, and distal end of radius was dislocated to dorsal side. Tenderness was prominent at the site of radial head and distal radioulnar joint. Surgical treatment was performed using triceps tendon strip. Good functional recovery was gained.

Lumbar diskal cyst containing intervertebral disk materials.

The diskal cyst is a relatively new clinical entity and develops clinical symptoms of a unilateral single nerve root lesion. Although many cases of diskal cyst have been reported, the pathogenesis of diskal cyst remains unclear, and several theories regarding the pathogenesis have been proposed. This article presents 2 cases of diskal cyst communicating with an adjacent herniated disk. Magnetic resonance imaging findings showed diskal cysts in the epidural space of the lumbar spine. Surgical resection was performed, and apparent connections between the corresponding disk and cysts were found. Histopathologic examinations of the cyst wall demonstrated cartilaginous tissue including nucleus pulposus and annulus fibrosis. These patient's symptoms improved remarkably postoperatively, and there was no recurrence of diskal cyst.The hypothesis supported by many authors is hemorrhage from the epidural venous plexus. Diskal cysts arise first from an underlying intervertebral disk injury that causes an annulus fibrosis fissure in the posterior intervertebral disk. Hemorrhage from the epidural venous plexus with a rich blood flow then occurs in the space between the peridural membrane and vertebral body. However, in our cases, we confirmed that the diskal cyst could have developed from the resorption process of an intervertebral disk herniation. Only 5 cases of diskal cyst demonstrating the presence of cartilaginous tissue in the cyst have been reported. Our 2 cases are rare and support the hypothesis of resorption of intervertebral disk herniation.

Ossifying fibromyxoid tumor: invariable ultrastructural features and diverse immunophenotypic expression.

Ossifying fibromyxoid tumor (OFMT) is a rare enigmatic soft tissue tumor, the origin of which is still uncertain. The authors report on 3 cases of OFMT arising in the trunk and head and neck regions of adults. Two recurred and one was suspected to have metastasis. All tumors consisted of multiple nodules, in which round or polygonal tumor cells were arranged in sheets or cords within a fibromyxoid background. Characteristic shell-like bone tissues were recognized in all tumors. Based on the grading system proposed by Folpe et al., 2 cases were designated as malignant OFMT and 1 as typical. In addition to S-100 protein, cytokeratin and neuronal markers (neurofilament, CD56 or CD57) were detected in 1 and 2 tumors, respectively. The salient and invariable ultrastructural features included reduplicated basal laminas, which seem to be crucial for the diagnosis.