Diagnostic pitfall: carbon monoxide poisoning mimicking hyperventilation syndrome.
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The significance of peritoneal washing cytology in the management of patients with gynecologic cancer is well established. Its microscopic evaluation, however, is not always straightforward. Previous studies have identified some of the conditions that may result in misinterpretation of cytologic results. This report reviews the literature and describes other sources of diagnostic difficulties and clues for correct diagnosis. In addition, an outline for distinguishing endosalpingiosis from borderline and well-differentiated serous carcinoma is proposed.
Skeletal scintigraphy (bone scanning) is a useful adjunct in the diagnosis of disease states, such as osteomyelitis, and in the evaluation of occult fractures. Certain conditions can alter the appearance of bone scans, such as age of the patient, prior use of antibiotics, concomitant diseases, and disruption of the vascular supply. Three patients whose clinical problems highlight diagnostic problems with bone scans are discussed.
Chondroblastoma of bone is a well-characterized entity. When the radiographic features are classic and the lesion is present in typical locations (i.e., epiphysis of a long bone), the diagnosis is often easily established by fine-needle aspiration biopsy and/or surgical curettage. Tumors in unusual locations, in older patients, or when complicated by aneurysmal bone cysts may pose more diagnostic difficulty. We report four examples (three primary and one-recurrent) of chondroblastoma of bone diagnosed by fine-needle aspiration biopsy. All patients were men, ranging from 18 to 28 yr of age. Sites of involvement included the acromion process of the scapula, left humerus, right ischium, and left distal femur. Three of the tumors were diagnosed as chondroblastoma on fine-needle aspiration cytology; the fourth case, involving the scapula, consisted mostly of a large aneurysmal bone cyst and remained unrecognized until surgical curettage was performed. Typical-appearing chondroblasts were present in three of the cases; osteoclast-type giant cells were observed in all four cases. Matrix material consistent with chondroid was also identified in all cases. We believe that in the absence of inflammatory cells, the presence of classic-appearing chondroblasts, even without chondroid matrix, is sufficient for a diagnosis of chondroblastoma of bone.
Computed tomography (CT) is the preferred method for evaluating the left periaortic infrarenal region. Structures larger than 11 mm in cross-sectional diameter in this region are considered abnormal and should be evaluated for lymphadenopathy, hydroureter, or a vascular abnormality such as venous thrombosis or varicoceles. Normal structures include inferior mesenteric vessels, left gonadal vein and artery, and ureter. The diagnostic process may be complicated by variations in anatomy, including double inferior vena cava, left inferior vena cava, retroaortic left renal vein, circumaortic left renal vein, horseshoe kidney, crossed-fused renal ectopia, renal agenesis, and ureteral duplication. Familiarity with the anatomy of this region and awareness of normal variants are necessary to avoid errors in diagnosis. Radiologists should also be aware of problems in CT technique (nonopacified bowel, dynamic and unenhanced scanning) that can confuse the diagnosis.
Although pilomatrixomas are well known to dermatologists and dermatopathologists, surgeons encountering these lesions over the parotid gland frequently do not consider this benign neoplasm in the differential diagnosis. Presentation of a subcutaneous preauricular lesion, coupled with an erroneous cytologic diagnosis of malignancy, can potentially result in histologic "overdiagnosis" and more aggressive therapy than is required for these benign hair follicle neoplasms. A case is reported to illustrate this potential diagnostic trap, and a series of 206 cases collected at the University Hospital of Zurich from 1975 to 1987 is reviewed.
The authors report on their clinical experience with Magnetic Resonance angiography (MRA) pitfalls. January, 1989, to February, 1995, six hundred MRA examinations were performed in different vascular districts, with a 1.5-T superconductive magnet, the time-of-flight (TOF) technique and 2D and 3D acquisitions. Intracranial arteries, epiaortic vessels and renal arteries were studied with FISP 3D sequences; intracranial veins, thoracic vessels, vena cava and pelvic vessels were studied with FISP 2D sequences. Pitfalls were observed in 56 of 600 MRA exams (9.3%). Of 56 pitfalls, 26 (46.4%) were in epiaortic vessels, 15 (26.7%) in intracranial vessels, 6 (10.7%) in renal arteries, 6 (10.7%) in thoracic vessels, 1 (1.7%) in the inferior vena cava and 2 (3.5%) in iliac vessels. Stenoses were overestimated in 21 patients and underestimated in three; 16 patients were misdiagnosed and 16 were false positives. As for cerebral vascular lesions, 5 aneurysms and 7 transverse sinus thromboses were false positives, while 3 lesions were misdiagnosed as venous angiomas. As for 26 MRA exams of thoracic vessels, stenoses were overestimated in 16 patients and underestimated in 10 patients with subclavian steal syndrome, where the left vertebral artery was misinterpreted as occluded. In 6 MRA exams of thoracic vessels, 1 patient was misdiagnosed as having an aneurysm and 5 patients were misdiagnosed as having lung cancer infiltrating aorta and superior vena cava. As for renal vessels, 2 normal renal arteries were misdiagnosed as false positives and 4 stenoses were overestimated. In the inferior vena cava, a partial agenesis was misinterpreted as thrombosis. In 2 MRA exams of iliac vessels, a stenosis and a thrombosis were misinterpreted as false positives. Our experience suggests that MRA pitfalls are caused by the incorrect use of the various techniques. The pitfalls we observed can be classified as caused by three types of artifacts: saturation, turbulence and paramagnetic substance artifacts.
Neuron-specific enolase-positive cells, some arranged in rosettes, were identified in smears obtained in fine-needle aspiration of a left retroperitoneal tumor found in a 3-yr-old boy. Nephrectomy showed a typical nephroblastoma with a prominent blastemic component revealing a positive reaction for neuron-specific enolase in blastemic and tubular components. Neuron-specific, enolase-positive, small malignant cells are not diagnostic of neuroblastoma when coming from a tumor of the retroperitoneum even if rosettes are present.
Pleural malignant mesothelioma (MM) usually presents with chest pain, pleural effusion, or cough in middle-aged and elderly individuals with a history of asbestos exposure, but may rarely present at unusual metastatic sites. The luminal gastrointestinal (GI) tract is only rarely involved in patients with wide-spread disease at autopsy. Encountering MM in endoscopic GI biopsies is an exceptionally rare event in surgical pathology practice and may therefore pose great diagnostic challenges if not considered, in particular if the clinical history is not informative or the GI symptoms are the presenting signs of the disease. To our knowledge, only three cases of epithelioid mesothelioma (EM) involving the luminal GI tract (intestine) have been reported so far, but no case of sarcomatoid MM (SM) involving the GI mucosa has been described. We herein present the first two cases of MM (one each of EM and SM) of the pleura, presenting in endoscopic gastric biopsies as small polypoid lesions and poorly healing ulcers 30 and 35 months after the initial diagnosis of pleural MM, respectively. The major differential diagnoses encompass primary or metastatic adenocarcinoma in case one and cytokeratin-positive (KIT negative!) GI stromal tumors (GISTs) and sarcomatoid carcinoma in case two, as well as other rare entities.
In this retrospective study (1981-1993) of 31 cases of esophageal perforations and ruptures circumstances the delay or misdiagnosis with undoubtable influence on the survival have been discussed. The over-all mortality was 16.1% but in cases of early (24 h) perforations or ruptures (12) no patients were lost. The unfavourable consequence of the superficial case history, underestimated pain, incomplete roentgenographic study, diagnostic confusion inadequate surgical exploration and misinterpreted postoperative complications of the formal esophageal surgery are analyzed. The authors emphasized the methods to decrease the number of the false-negative contrast esophagograms as well as the value of the intraoperative endoluminal diluted methylin-blue injection to detect esophageal leak. The early diagnosis is the first prerequisite for a favourable outcome in this life-threatening emergency.
Benign renal tubular cells and renal-cell carcinomas (RCC) may have intracytoplasmic hemosiderin (ICH). The RCC subtype most commonly reported to contain ICH is papillary carcinoma (PRCC). PRCC, usually a low-grade neoplasm, may be associated with cystic degeneration, hemorrhage, and presence of abundant hemosiderin-laden macrophages (HLM). We report a case of PRCC with massive ICH and HLM that created a diagnostic challenge to differentiate from a hemorrhagic cyst. Review of 14 additional nephrectomy specimens with PRCC disclosed ICH in 3 cases. All had coexisting cystic change and hemorrhage. Preoperative FNA had been performed in one of these cases, and both ICH and HLM were found. Papillary epithelial cell features, however, were well-defined in this case. PRCC should be considered in the differential diagnosis of cystic renal lesions with hemosiderin-laden cells. Differentiation of HLM from neoplastic cells with massive ICH may be difficult, especially when epithelial fragments are scanty.
We report the case of an azygos vein aneurysm that was found intraoperatively in a 66-year-old woman followed for esophageal carcinoma. She underwent video-assisted thoracoscopy surgery (VATS) for biopsy of a mediastinal mass. This mass was diagnosed in the 2nd year of postoperative follow-up for a T2N0M0 esophageal carcinoma by computed tomography, which revealed a heterogeneous mass of ~2 cm in diameter in a retrotracheal location. Preoperative echoendoscopy demonstrated an extraesophageal lesion. A diagnostic thoracoscopy was done in order to exclude a metastatic lymph node disease.
Pulmonary sequestration is defined as a congenital malformation of abnormal lung tissue that does not communicate with the airway system and that receives blood supply from anomalous arteries. The majority of these sequestrations are encountered in the pediatric population. Surgical excision is the treatment of choice, with excellent prognosis. We studied a case of an extralobar pulmonary sequestration in a young adult, presenting as an intrathoracic mass; it was aspirated twice, final diagnosis being rendered after surgical resection. The cytologic findings and the accompanying diagnostic difficulties to our knowledge have never been reported.
CD31 (platelet endothelial adhesion molecule, PECAM-1) is generally regarded to be the most sensitive and specific endothelial marker in paraffin sections. We have recently encountered several cases in which intratumoral CD31-positive macrophages were misinterpreted as evidence of a vascular sarcoma. We therefore reviewed our last 1950 consultation cases with respect to cases in which CD31 immunostains were performed, to determine the frequency of CD31 expression in macrophages in formalin-fixed, paraffin-embedded tissue and how often the presence of these cells was a source of diagnostic confusion. CD31 immunohistochemistry had been performed on 59 of 1950 (3%) of cases. These 59 cases consisted of both vascular (20 cases) and nonvascular tumors (39 cases). CD31-positive macrophages were distinguished from endothelial or tumor cells by correlation with the morphologic features and the immunohistochemical staining pattern of the cells of interest. In no case was CD31 positivity seen in the lesional cells of a nonvascular tumor. CD31-positive macrophages were identified in 48 of 59 (81%) cases. CD31-positive macrophages were present in 34 of 39 (87%) nonvascular tumors. A vascular tumor was diagnosed or favored by the referring pathologist in 15 of these 39 cases (38%). In 14 of these 15 cases CD31 immunostains were performed by the referring pathologist; 13 (93%) showed CD31-positive macrophages. In 4 of these 14 cases (29%) the misdiagnosis of a vascular tumor was based primarily or in part on the misinterpretation of CD31-positive macrophages as tumor cells. In all cases with CD34 and CD68 immunostains, the CD31-positive macrophages were CD34 negative and CD68 positive. We conclude that CD31 expression is very common in macrophages. Misinterpretation of CD31-positive macrophages as tumor cells may result in the erroneous diagnosis of a primary vascular neoplasm. Recognition of the characteristic granular, membranous pattern of CD31 expression in macrophages and careful distinction from tumor cells should allow the accurate interpretation of CD31 immunohistochemistry in possible vascular neoplasms. CD31 may also be useful as a nonlysosomal marker of macrophages in formalin-fixed, paraffin-embedded sections.
The clinical and neuro-endocrine data of seven young male patients with suprasellar germinomas seen between 1984 and 1992 are reported. The most common initial symptom was 'idiopathic' central diabetes insipidus (DI), which occurred in all seven patients. The time interval between the appearance of this first clinical sign and the definitive diagnosis of a suprasellar germinoma ranged from 3 to 66 months. Raised prolactin levels and growth hormone deficiency were indicators of a process located in the hypothalamic-pituitary region. An increased beta-HCG level in the serum or the CSF confirmed the diagnostic suspicion of a germinoma and was helpful as a tumor marker in follow-up. Neuro-radiologic studies (CT or MRI) were also disappointing in the early stage when patients presented only with DI. Later on, as patients developed additional symptoms or signs related to the tumor, imaging studies were positive. Given the variable rate of tumor progression, the nonspecific early signs of hypothalamic-pituitary dysfunction (DI) as well as the often negative early imaging studies, the diagnosis of suprasellar germinoma is difficult but should always be considered in the presence of so-called 'idiopathic' central DI. Repeated brain MRIs are mandatory in young patients with idiopathic DI in order not to miss an underlying suprasellar germinoma.
Central diabetes insipidus (CDI) is a rare disorder that may be caused by a variety of diseases. In pediatric and adolescent patients the most common causes for CDI are Langerhans cell histiocytosis (LCH) and germinoma. To avoid a potentially hazardous biopsy of the hypothalamic pituitary region it is recommended to evaluate patients with CDI carefully to identify potential extracranial lesions. Since LCH is the most common systemic disease that may cause CDI, special focus is paid to the identification of LCH lesions. We report on a 9(1/2) year old girl who presented with central diabetes insipidus and a thickening of the pituitary stalk on magnetic resonance imaging. Diagnostic workup revealed a history of recurrent ear infections and a compressed 6th thoracic vertebral body on radiographs. Based on these findings LCH was anticipated. Upon growth of the pituitary stalk lesion the patient was treated with LCH standard chemotherapy. After an initial shrinkage of the lesion, a further growth of the pituitary stalk lesion was observed and the tumor was resected. Histopathology revealed germinoma. This case underscores the importance of a istopathologically proven diagnosis in patients with HPR tumors before the initiation of a specific therapy, even if the clinical findings are highly suggestive.
In the upper aerodigestive tract, respiratory epithelial adenomatoid hamartoma (REAH) is described as a polypoid proliferation of glands lined by ciliated respiratory epithelium that seem to invaginate downward into the submucosa while maintaining direct continuity with the surface mucosa. The lesion can be confused with a variety of benign and malignant entities, including inflammatory polyp, inverted schneiderian papilloma, and low-grade sinonasal adenocarcinoma. In reviewing the historical, clinical, gross, and histopathologic features of REAH and its subtypes, we elucidate how the distinction of REAH with florid mucinous metaplasia from low-grade adenocarcinoma can be challenging particularly in the setting of small biopsy samples. Diagnostic criteria are reviewed with emphasis on key distinguishing characteristics. The significance of this distinction is paramount in preventing unwarranted surgery and untoward consequences for the patient.
We report on a 75-year-old woman who presented recurrent bilateral ankle pain and swelling related to insufficiency fractures. The diagnosis of this rare condition is difficult since the initial X-rays are usually normal. We may expect an increased frequency of insufficiency fractures of unusual bones with aging of the population.