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Objective: This paper describes the dental elements (i.e., teeth and incomplete tooth-like structures) formed by mature cystic teratomas and provide some diagnostic criteria to aid in their paleopathological identification and analysis., Materials: Hard tissue structures from 13 clinically-derived mature cystic teratomas excised between 2003 and 2007. All are from female patients (N = 13) between the ages of 17 and 56., Methods: A dental and osteological inventory identified number of teeth and tooth types present in each specimen., Results: Of the 13 specimens, nine contained dental elements. The number per teratoma ranged from one to seven. A wide variety of tooth types were present in the teratomas with some teeth independent of, and others embedded within, bony matrices., Conclusions: While some teratoma teeth exhibit distinguishable types and laterality, the majority will exhibit some degree of abnormality in size, form, developmental completion, or association with other irregular bony elements., Significance: Give the modern clinical prevalence and yet relatively few paleopathological cases reported, it is likely that mature teratomas are under-identified in the archeological record. The diagnostic criteria presented in this paper can aid paleopathologists in their identification and analysis of these neoplasms., Limitations: Precise paleopathological identification of teratoma elements can be difficult; particularly when they are no longer constrained or contextualized by unmineralized neoplastic borders. As such, there is a risk that such remnants may be mistaken for fetal parts or disassociated elements., Suggestions for Further Research: Application of these criteria, paired with careful excavation techniques, is advised., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Diatoms are photosynthetic algae with a siliceous exoskeleton. Diatoms are utilized by a wide array of industries for applications such as filtration and pest control. Unsubstantiated claims have also propelled their societal reach to trendy oral and topical uses. This case highlights a rare case of an oral granuloma secondary to diatoms. An 80-year-old woman presented with a mobile, firm, asymptomatic submucosal mass on her lower left mandibular vestibular mucosa. Histopathology showed a non-caseating granulomatous reaction to diatoms. Her only verified contact with a diatomaceous earth product was a dental impression using alginate after upper front teeth trauma 5 months before. Although there have been several cases of allergic contact dermatitis attributed to diatoms, there are no reported cases of diatom-induced granuloma formation found in the literature. There are, however, ample data on granulomas initiated by silica. Given the silica-based composition of diatoms, and the broad use of diatoms in industry and alternative medicine, it is unclear why diatom-induced granulomas are not more widely described. This report may alert clinicians to the existence of diatom granulomas and incline them to tailor their history to cover questions about possible exposure when evaluating patients presenting with a localized oral lesion., (© 2020 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Unlike modern diagnosticians, a paleopathologist will likely have only skeletonized human remains without medical records, radiologic studies over time, microbiologic culture results, etc. Macroscopic and radiologic analyses are usually the most accessible diagnostic methods for the study of ancient skeletal remains. This paper recommends an organized approach to the study of dry bone specimens with reference to specimen radiographs. For circumscribed lesions, the distribution (solitary vs. multifocal), character of margins, details of periosteal reactions, and remnants of mineralized matrix should point to the mechanism(s) producing the bony changes. In turn, this allows selecting a likely category of disease (e.g. neoplastic) within which a differential diagnosis can be elaborated and from which a favored specific diagnosis can be chosen., (Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.)

Amelanotic melanoma (AM) is a rare form of melanoma which lacks visible pigment. Due to the achromic manifestation of this atypical cutaneous malignancy, it has been difficult to establish clinical criteria for diagnosis. Thus, AM often progresses into an invasive disease due to delayed diagnosis. In this report, we describe the case of a 72-year-old Caucasian woman who had been diagnosed with AM after 3 years of failed treatments for what presented as a periorbital dermatitis. Her Clark's level 4, 1.30 mm thick melanoma required nine surgeries for successful resection and reconstruction. This case exemplifies the diagnostic pitfall of AM and the need for new criteria for early detection and management., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Drug rash with eosinophilia and systemic symptoms (DRESS) is a rare but potentially life-threatening condition with high mortality. Diagnosis is challenging due to variable clinical presentation and a protracted latency period following initiation of the offending drug. DRESS is a complex interplay that starts by introduction of the offending drug, reactivation of viruses and activation of the immune system. Herpes virus reactivation is considered a diagnostic marker and indicator of illness severity. Prompt recognition and the removal of offending agent remain the key to successful treatment. In cases of severe organ involvement, corticosteroids, immunoglobulins, antiviral and specialist consultation may be helpful. Here we present a case of a 36-year-old African-American male who presented with symptoms mimicking sepsis with an associated skin eruption that was diagnosed as DRESS., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Cutaneous injuries due to industrial high-pressure paint guns are well-documented in the literature; however, the histologic characteristics are uncommonly described, and facial involvement has not been previously reported. Histopathologic features of paint gun injuries vary depending on the time since injection and type of material. Early lesions display an acute neutrophilic infiltrate, edema, and thrombosis, with varying degrees of skin, fat, and muscle necrosis. More developed lesions (120-192 hours after injury) have prominent histiocytes and fibrosis around necrotic foci, possibly with the pitfall of muscle regenerative giant cells that could be mistaken for sarcoma. Continuing inflammation, swelling, and resultant vascular compression could explain ongoing necrosis months after the accident. The histopathologic differential diagnosis in the absence of clinical history includes paint in an abrasion, foreign body reaction to tattoo, giant cell tumor of tendon sheath, and various neoplasms. If available, radiologic studies can substitute for clinical photographs to indicate the extent of injury. The radiologic differential, uninformed by history, may include calcific periarthritis, gouty tophus, and tumoral calcinosis. Seven cases of injury due to high-velocity paint guns are presented with 4 additional cases mimicking paint gun injury and with review of the literature.

Soil and freshwater-dwelling amoebae may opportunistically infect the skin and evoke a granulomatous dermatitis that camouflages their underlying morphology. Amoebic infestations are incredibly rare in the U.S., predominantly occurring in the young, elderly, and immunocompromised. Sadly, because diagnosis is difficult and unsuspected, most cases are diagnosed at autopsy. The following case is of a healthy 84-year-old man with a non-healing nodulo-ulcerative cutaneous lesion on his left forearm that appeared following a gardening injury. Lesional punch biopsies repeatedly showed non-specific granulomatous inflammation with no pathogens evident histologically or by culture. Histopathologic diagnosis was made five months after initial presentation via identification of amoebic trophozoite forms in tissue from a large excisional specimen. Anti-amoebic therapy was initiated immediately. The patient experienced mental status changes three days following lesion excision, with evidence of a cystic mass in the left medial parieto-occipital lobe by CT. Both intraoperative brain biopsies and cutaneous tissue samples tested positive for Balamuthia mandrillaris by indirect immunofluorescent antibody assay performed at the Centers for Disease Control. The patient achieved a full recovery on a triple antibiotic regimen. Clinical suspicion and thorough histopathologic analysis may determine the difference between survival and death for a patient presenting with a treatment-refractory localized granulomatous lesion.

Ischemic fasciitis is a pseudosarcomatous nodule or mass resulting from sustained or repeated pressure and consequent ischemia of soft tissue. Fibrin and hemorrhage expand its hypocellular epicenter bordered by enlarged (atypical, ischemic) fibroblasts and reactive vascular prominence resulting in diagnostically important histologic zonation. Although classically in bedridden patients, ischemic fasciitis owing to posture-related intermittent pressure in ambulatory adults is not well characterized; there has not been a thorough review of its presentation in ambulatory patients in the dermatology/dermatopathology literature. This article reviews the clinical, pathologic and radiologic presentation of 17 cases of ischemic fasciitis diagnosed over a 14-year period. Eighty-six percent of the six cases submitted by non-dermatologists were limb girdle/trunk lesions averaging 6.7 cm in greatest diameter while 90% of the eleven lesions submitted by dermatologists were elbow and forearm lesions averaging 2.3 cm. In no case was the diagnosis anticipated pre-biopsy by clinician or radiologist. Dermatologists submitted the majority of cases. Because ischemic fasciitis may simulate soft tissue sarcoma clinically and histologically, diagnosis helps prevent overtreatment. Zonal histopathologic structure may be shown by any form of biopsy and should motivate correlation with available radiologic studies. Importantly, determining a history of postural pressure at the site confirms the histopathologic diagnosis and avoids unnecessary excision., (© 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

We report the case of a 34-year-old woman who was diagnosed with pemphigus vulgaris (PV) during pregnancy. The patient presented with widespread blistering dermatitis and associated burning and pruritus. At 6 weeks' gestation the patient was admitted to the hospital to expedite her diagnosis and initiate treatment. A skin biopsy revealed suprabasal acantholysis, and direct immunofluorescence demonstrated diffuse intercellular IgG in the epidermis and basal intercellular C3, which confirmed the diagnosis of PV. Treatment with corticosteroids was instituted after discussions with the patient about possible adverse effects to the fetus. Pemphigus vulgaris is rare in pregnancy and active PV presents potential threats of fetal spread and transient lesion production, which is associated with increased mortality and morbidity in the fetus. Our patient had active PV and required treatment throughout her pregnancy. The pregnancy progressed to premature delivery of the neonate without skin lesions or apparent complications.

Cutaneous Pneumocystis jirovecii infection is rare. It is thought that the disease emerges from a latent infection delivered via hematogenous and/or lymphatic dissemination from a primary lung infection in immunocompromised individuals. A 32-year-old human immunodeficiency virus-positive male was admitted for headache and vomiting. He was diagnosed with meningitis due to Cryptococcus neoformans and sputum tested positive for Pneumocystis. Six months later, he presented with a slightly crusted yellowish brown plaque and 2 similar but smaller papules with telangiectasia near the right angle of the mouth. Biopsy of the area featured histiocytes expanded by foamy cytoplasm as in a xanthoma except that the vacuoles were coarser. Special stains ultimately demonstrated the characteristic disks of Pneumocystis accompanied by a minor component of budding yeasts (Cryptococcus) in the same fields. This case illustrates the utility of adequate special stains in recognizing a mixed cutaneous infection, particularly in human immunodeficiency virus-positive patients, when microscopy presents an odd xanthoma-like lesion.

Background: Calcific periarthritis, referring to a circumscribed juxta-articular deposit of minute non-birefringent mineral grains, is rarely the clinical diagnosis accompanying a pathologic specimen. Familiarity with the clinical, pathologic, and radiologic manifestations of calcific periarthritis, particularly when encountered adjacent to joints other than the shoulder, facilitates diagnosis and may obviate biopsy, avoid confusion with other entities, and speed appropriate treatment., Methods: Pathologic specimens that fulfilled the criteria for a diagnosis of calcific periarthritis were prospectively collected. Clinical history and radiologic studies were acquired and analyzed. Well-controlled special stains were employed on two specimens with a neutrophilic infiltrate that excluded fungal and bacterial agents, as corroborated by microbiologic cultures showing no growth., Results: Over a five-year period, fifteen patients between the ages of thirty-one and eighty-eight years (mean age, fifty-nine years) presented to various local healthcare providers for treatment of juxta-articular swelling that was subsequently determined to be calcific periarthritis. In seven patients, deposits were alongside a toe joint; in five, alongside a finger joint; and in three, involving the shoulder. The majority of the patients were female (73%). No patient had a documented recurrence of calcific periarthritis in follow-up periods ranging from eighteen to eighty-seven months (average forty-five months)., Conclusions: Of twelve histologically verified cases of calcific periarthritis adjacent to joints other than the shoulder, in only one patient (toe) was the preoperative clinical diagnosis accurate, which signals the need for greater awareness of this entity as a differential diagnostic option.

Osteomas of the cranial sinuses are rare, benign bony tumors that can be complicated by the formation of an intracranial pneumatocele. If not treated promptly, a pneumatocele can lead to abscess formation, meningitis, or ventriculitis. In the present case, an intracerebral pneumatocele was formed when an 18 cm(3) osteoma breached the posterior wall of the frontal sinus creating a one-way valve through which air could enter the intracranial cavity. The patient presented after forceful sneezing with nonspecific symptoms of headache, nausea, and vomiting. CT demonstrated a frontal collection of loculated air with mass effect within the left cerebral hemisphere. A partly mineralized mass occupied the left superior nasal ethmoid sinus and left frontal sinus. Of interest pathologically in this case, the tumor had a substantial osteoblastoma-like component. Surgical repair involved frontal craniotomy to remove the osteoma and debride frontal sinus mucosa, plugging the frontal nasal ducts and sinus with fat and bone wax, and dural restoration using an underwater closed drainage system to vent intracranial air and stabilize the patient.

Mucoepidermoid carcinoma is a relatively common neoplasm of the major and minor salivary glands that can secondarily involve skin. In the vicinity of the ear lobe, mimicry of a benign cyst, both clinically and histopathologically is a diagnostic pitfall to avoid. The clinical manifestations, diagnostic histopathology, and clinical course of mucoepidermoid carcinoma of the parotid gland presenting as a clinically benign periauricular cystic nodule in four patients ranging in age from 11 to 63 years, are analyzed in the present report. Illustrating the challenge of accurate diagnosis, three of the four cases were initially misinterpreted on biopsy as benign cystic lesions. Multiple biopsies displayed foamy histiocytes around mucinous extravasations into dermis that mimicked ruptured epithelial cysts in two cases before malignancy was ascertained. This series demonstrates the need to include parotid tumor in the differential diagnosis of odd periauricular cyst-like expansions and adenosquamous proliferations. Mucoepidermoid carcinoma in particular can explain indolent, infra-auricular 'mucinous cysts'. Familiarity with this syndrome should arouse suspicion of parotid carcinoma when a 'cyst' or nodule is located near the earlobe. Delay in diagnosis results in larger surgical procedures than are otherwise necessary., (Copyright © 2012 John Wiley & Sons A/S.)

Acquired acro-osteolysis (AOL) is defined as the resorption of bone from the tufts or shafts of the terminal phalanges. Acquired acro-osteolysis can manifest as a primary osteolysis syndrome and also appears in a number of disease states including rheumatologic disorders, neuropathic diseases, the result of prolonged exposure to polyvinyl chloride, and in rare cases, as a response to repeated mechanical stress. In this report, a 46-year-old surfer was evaluated for AOL as a complication of sports-related repetitive trauma to the right second and third toes. Radiography showed the bony tips of his right second and third toes had been eroded away. Acquired acro-osteolysis in the surfer's toes resulted from increased blood flow initiated to repair microdamage caused by repeated trauma to the distal ends of his second and third right toes due to the habitual dragging of the affected toes across a surfboard. The always initial lytic phase of bone repair was magnified by the increased arterial input to warm the extremities after prolonged exposure to cold. At 6-years' follow-up, the use of a protective bandage while surfing has permitted full regeneration of the affected toes.

Amelanotic melanoma, a renowned impersonator, has taken on a new persona. A 63-year-old woman was seen in the emergency room with a chief complaint of back pain after a fall and was discovered to have a 15-cm fungating mottled gray mass independent of bone on the right elbow. Initial workup discovered lytic calvarial lesions, anemia (Hb 7; Hct 20%), and circulating plasma cells consistent with plasma cell myeloma. Biopsy of the elbow mass displayed sheets of plasmacytoid cells, some reactive for CD138. Flow cytometry revealed a substantial portion of the plasma cells in the tumor that were kappa restricted consistent with cutaneous plasmacytoma. The elbow mass was initially signed out as extramedullary involvement by her myeloma. Reevaluation of the mass after the patient experienced an explosive growth of multinodular jet black malignant melanoma on ipsilateral breast revealed MART-1 and S-100 reactivity of the majority of the cells. In retrospect, the elbow mass was a neglected primary amelanotic malignant melanoma with neoplastic plasma cells participating in its chronic inflammatory infiltrate.

A plastic bag clip was incidentally found anchored in the mucosa of a partial colectomy specimen 2.6 cm proximal to a ruptured diverticulum for which the patient, a mentally retarded, diabetic, 58-year-old man, underwent surgery. Over 20 cases of accidental ingestion of plastic bag clips have been published. Known complications include small bowel perforation, obstruction, dysphagia, gastrointestinal bleeding and colonic impaction. Preoperative diagnosis of plastic clips lodged in the gastrointestinal tract is frustrated due to radiographic translucency. This occult threat could likely be prevented by the design of gastrointestinally safe, plastic-bag-sealing devices. Presented here is a morphologically based classification of bag clips as a possible guide for determining the most hazardous varieties and to aid further discussions of their impact on health.

Dermatofibroma (DF), also referred to as cutaneous fibrous histiocytoma (CFH), is a common tumor of the skin presenting as a firm nodule located predominantly on the limbs and shoulder and pelvic girdles that often extends into superficial subcutaneous tissue. This is a retrospective study of 26 DFs located on digits. All case slides were retrieved from saved files for diagnostic verification. One case was rejected after revision of the diagnosis to giant cell tumor of the tendon sheath. The 26 remaining cases constitute this reported series. Digital DFs affected 27 to 70 year-olds in a 2.25:1 male to female ratio. The most common clinical diagnosis submitted was "growth" or wart. In only 6 out of the 26 cases was the pre-biopsy diagnosis of DF ventured. Although lesional tissue went to dermal margins in 14 specimens, only one has been re-excised in follow up ranging from 2 months to 10 years. Because DFs can resemble several entities including leiomyosarcoma and dermatofibrosarcoma protuberans, a lack of familiarity with the occurrence of DF on the digits may result in more aggressive treatment than otherwise necessary. DF should be in the differential diagnosis of circumscribed, firm nodules presenting on the digits.

As a primary malignant bone tumor, osteosarcoma is second only to chondrosarcoma. Although it commonly metastasizes and is aggressive in nature, it rarely colonizes the skin. This is a report of a 22-year-old male with osteosarcoma of the pelvis and metastasis to the lungs and chest wall who developed a clinically unsuspected solitary cutaneous metastasis in the scalp. Instead of the expected cyst, incisional biopsy disclosed a solid tan nodule of chondro-osseous sarcoma. Although rare, cutaneous metastases from osteosarcoma may appear in skin, especially the scalp, or in skin over the primary tumor. New skin lesions in a patient with a history of osteosarcoma warrant investigations including imaging and biopsy.

Palisaded encapsulated neuroma (PEN; solitary circumscribed neuroma) is a benign, morphologically characteristic cutaneous or mucosal neuroma. Most are solitary lesions on the face, neck or oral mucosa. Histologically, the majority appears as dermal nodules of Schwann cell-rich fascicles, with or without distinctive encapsulation. To further expand on the existing literature regarding this neuroma, we herein describe three PENs with unique clinical and histopathologic features. All occurred on the acral skin, a rarely described site. Furthermore, one exceptional patient presented with multiple PEN on the bilateral hands, biopsies of which showed a prominent plexiform architecture. Awareness that PEN may occur on acral skin, may rarely present as multiple lesions, and recognition of the plexiform variant is important because PEN may histologically mimic other peripheral nerve sheath tumors. Additionally, misdiagnosis may have significant clinical implications., (Copyright © 2009 John Wiley & Sons A/S.)

Pigmented epithelioid melanocytoma (PEM) is a recently described entity encompassing epithelioid blue nevus (of Carney complex) and most tumors earlier considered as so-called "animal-type melanoma". Loss of expression of a Carney complex gene, cyclic adenosine 3',5' monophosphate-dependent protein kinase regulatory subunit 1alpha, is observed in the majority of PEMs. Initial reports with short-term follow-up have suggested that although PEMs frequently metastasize to lymph nodes, they have a more favorable outcome than conventional melanomas. In this report, we present the results of long-term follow-up in 26 patients with PEMs from North America and Australia. There were 9 males and 17 females, with a median age of 20 years. The tumors involved the trunk (6 cases), extremities (12 cases), genitalia (1 case), and the head and neck region (7 cases) had a median Breslow thickness of 2.2 mm (range 0.80 to 10.0 mm) and a median Clark level of 4. Eight of the patients developed lymph node metastases. After a median follow-up period of 67 months (range 39 to 216 mo), all patients are alive and free of disease. These findings provide further evidence that PEM is a unique low-grade melanocytic tumor with limited metastatic potential (to lymph nodes), but a favorable long-term clinical course.

Alveolar rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma of childhood. It typically has middle ear/temporal bone and nasopharynx as its most common head and neck sites. In fact, 'middle ear' is what is meant by 'ear' location in the many reports of pediatric RMS. This case report, however, is of RMS occurring on the external ear of a young female. RMS in skin should motivate a search for an occult extremity or visceral tumor, which was not present in this case.

A cyst following implantation of respiratory epithelium during surgical procedures has been documented only rarely. A variety of names have been attached to this lesion: respiratory mucocele, respiratory implantation cyst, surgical ciliated cyst, and surgical (implantation) cyst. In seven prior case reports, the interval between the initiating surgical procedure and diagnostic biopsy of the resultant well-circumscribed radiolucency and histopathological demonstration of distinctive pseudostratified ciliated columnar epithelial lining has varied from 4 to 40 years. In the case reported here, chin augmentation used "residual maxillary bone" as the donor tissue and likely transplanted sinonasal mucosa into the mandible during orthognathic surgery, resulting in a painful anterior mandibular cyst lined by respiratory epithelium that was ablated 16 years later.

The potential and reliability of DNA analysis for the identification of human remains are demonstrated by the study of a recent bone sample, which represented a documented case of sickle cell anemia. beta-globin gene sequences obtained from the specimen revealed homozygosity for the sickle cell mutation, proving the authenticity of the retrieved residual DNA. Further investigation of mitochondrial and Y chromosome DNA polymorphic markers indicated that this sample came from a male of maternal West African (possibly Yoruban) and paternal Bantu lineages. The medical record, which became available after the DNA analyses had been completed, revealed that it belonged to a Jamaican black male. These findings are consistent with this individual being a descendent of Africans brought to Jamaica during the trans-Atlantic slave trade. This study exemplifies how a "reverse population genetics" approach can be applied to reconstruct a genetic profile from a bone specimen of an unknown individual., (Copyright 2000 Wiley-Liss, Inc.)

Herbicides, chlorophenols, and other occupational exposures are suspected risk factors for soft-tissue sarcoma, but the epidemiologic evidence is inconsistent. Given that soft-tissue sarcomas represent a heterogeneous mix of cancer subtypes and that these subtypes have different disease patterns by race, sex, and age at diagnosis, studying all soft-tissue sarcomas combined may mask subtype-specific associations. Using the Selected Cancers Study, a large population-based case-control study of sarcoma conducted among U.S. men aged 30 to 60 in 1984 to 1988, we explored the occupational risk factors for soft-tissue sarcoma subtypes and skeletal sarcoma. The analysis included 251 living sarcoma cases (48 dermatofibrosarcoma protuberans, 32 malignant fibrohistiocytic sarcoma, 67 leiomyosarcoma, 53 liposarcoma, and 51 skeletal sarcoma) and 1908 living controls. Exact conditional logistic regression models suggested patterns of subtype specificity for occupational exposures. Self-reported herbicide use was associated with malignant fibrohistiocytic sarcoma (OR = 2.9, 95% CI = 1.1-7.3). We found elevated risks for chlorophenol exposure and cutting oil exposure and malignant fibrohistiocytic sarcoma and leiomyosarcoma. We found no occupational risk factor for liposarcoma. Polytomous regression models identified different odds ratios across subtypes for plywood exposure and exposure to wood and saw dust. Although exploratory, this analysis suggests that occupational risk factors for sarcoma are not uniform across subtypes.

To evaluate the association of chlorophenol exposure with soft tissue sarcoma risk independent of phenoxyherbicide exposure, the authors analyzed data from the Selected Cancers Study, a population-based case-control study that included 295 male soft tissue sarcoma cases, aged 32-60 years, from eight population-based cancer registries and 1,908 male controls. Chlorophenol exposure was assigned using both an intensity and a confidence estimate by an industrial hygienist based on verbatim job descriptions. Seventeen percent of the jobs rated as high intensity involved wood preservation, while 82% involved cutting oils. Soft tissue sarcoma risk, modeled using conditional logistic regression, was significantly associated with ever having high-intensity chlorophenol exposure (odds ratio = 1.79, 95% confidence interval 1.10-2.88). A duration-response trend was evident among more highly exposed subjects (p for trend < 0.0001). For subjects with 10 or more years of substantial exposure, the odds ratio was 7.78 (95% confidence interval 2.46-24.65). These results suggest that chlorophenol exposure independent of phenoxyherbicides may increase the risk of soft tissue sarcoma. Because of the large number of machinists in the exposed group and the complex composition of cutting fluids, it is possible that another exposure involved in machining is responsible for the observed excess risk.

Juvenile active ossifying fibroma is a rare lesion seldom seen by neurosurgeons. It originates in the paranasal sinuses during childhood, grows slowly, and encroaches on adjacent orbital and cranial compartments. In the past 3 years, four patients with this lesion were seen (three men and one woman; mean age 28 years). The clinical presentations were different with each patient: sinusitis, meningitis, periorbital pain, and a unique case of a juvenile active ossifying fibroma presenting with high-grade internal carotid artery stenosis and ischemic symptoms. Three patients were treated by transfacial approaches: two with a transfrontal-nasal approach and one with a transfrontal-nasoorbital approach. Two open resections resulted in gross-total excision and no recurrence as of the 2-year follow-up review. In the third patient, the tumor-encased carotid artery was preserved at the expense of a complete resection; that patient underwent superficial temporal artery-middle cerebral artery bypass and remains without ischemic symptoms or tumor recurrence at 2 years. The fourth patient underwent three subtotal endoscopic resections and is also without symptomatic recurrence at 2 years. Three points must be made concerning these lesions. First, the clinical and radiographic characteristics of juvenile active ossifying fibroma may not be easily recognized by neurosurgeons, which could lead to misdiagnosis and mismanagement of these lesions. Second, this tumor can encase the carotid artery and cause severe stenosis or occlusion. Third, complete resection of the tumor is required to effect a cure, and transfacial approaches, which give wide exposure of the sinuses, appear to yield better, more radical resections than endoscopic procedures.

Atypical fibro-osseous lesions, usually in the proximal femur, are a common consultative diagnostic problem. This is due to the fact that they contain a variety of patterns individually reminiscent of fibrous dysplasia, fibroxanthoma (non-ossifying fibroma), myxofibroma, lipoma, cyst, bone infarct, Paget's disease, and, occasionally, chondroma. The variety of patterns in a single lesion precludes a simple designation. A diagnosis based on the predominant pattern would ignore this histologic complexity, which can be predicted by location in the proximal femur and a distinctive radiographic configuration. Personal experience with 95 heterogeneous lesions indicates they are usually incidental findings. They have a broad adult age range, but quite likely have their inception in childhood and slowly alter their appearance over a lifetime. In the majority of instances asymptomatic discovery, lack of distortion of bone outline, and sclerotic borders are indications of stability over many years. Other lesions gradually enlarge, predisposing to pathologic fracture. In parallel with some enchondromas and bone infarcts, a minority of lesions undergo malignant transformation.

Parosteal lipomas, benign adipose tissue tumors situated directly on bone cortex, are unusual neoplasms that appear to emerge from multidirectional mesenchymal "modulation" within the periosteum. These tumors have been described as "periosteal lipomas", "chondrolipomas of soft tissue" and "lipomas of nerves" but they are most commonly believed to originate from the periosteum. Although over 100 of such tumors have been described in the literature, they have not been the subject of a comprehensive review, nor their potential for chondroid modulation and enchondral ossification emphasized. A review of 14 parosteal lipomas from the Bone Tumor Registry, Armed Forces Institute of Pathology, indicates these tumors are frequently associated with chondroid and/or osseous modulation, which permits subclassification into 4 distinct variants. Each of the 4 subtypes (I: No Ossification; II: Pedunculated Exostosis; III: Sessile Exostosis; IV: Patchy Chondro-Osseous Modulation) is illustrated to demonstrate the morphologic basis for radiologic/pathologic correlation and subclassification. A brief overview of the literature and pathogenesis of this unusual lesion is presented and discussed.

A trabecular (Merkel cell) carcinoma arising in the wall of an epidermal cyst in a 58-year-old white male metastasized, 17 months after local excision, to an inguinal lymph node. Ultrastructural studies showed polygonal tumor cells with typical dense-core granules. Although squamous-cell carcinoma and other malignant neoplasms have been reported rarely to have arisen in epidermal cysts, a literature search failed to find a precedent for the present case.

Clinical and radiological signs of a chiasmal lesion developed in a man 25 years after successful treatment of tuberculous meningitis. Surgical exploration and pathological examination demonstrated a mature chiasmal osteoma. The bony growth may have been a sequela of the prior infection.

Severely impaired musculoskeletal mobility in C3H-A(vy) mice was noted during a pharmacologic trial evaluating the antitumorigenic properties of retinyl acetate (RAc). To determine the etiology of this impairment, we studied 103 female C3H-A(vy) mice that were fed RAc in daily doses of 75-300 micrograms or placebo and were killed after 3-16 months. Whole-body radiographs and histologic sections of the hindlimbs were scored for presence and severity of arthritis. C3H-A(vy) mice treated with RAc in any dose had a significantly higher incidence of arthritis than placebo-treated mice. Histologic evidence of enthesopathic disease closely paralleled the radiographic changes and ranged from small enthesophytes at tendinous and capsular insertions to complete periarticular bony bridging. Articular cartilage was not grossly affected. The incidence and severity of arthritis were significantly correlated with the total dose of RAc administered. The bony metaplasia induced by RAc was similar to the pathologic changes caused by other retinoids. This model may be useful for studying the pathogenesis of periarticular bone formation in diffuse idiopathic skeletal hyperostosis and related syndromes.

The clinical and pathologic features in 21 cases of a distinctive solitary fibro-osseous lesion affecting the orbit distinguished histologically by the dominance of numerous small round "psammoma-like" ossicles embedded in a cellular benign spindle cell stroma were studied. The patients were predominantly young, and 19 of the lesions were centered on the orbital plate of the frontal bone or ethmoid. A clinical course of slowly progressive symptoms over several years was typical but not uniform. The most common clinical diagnosis was fibrous dysplasia and mucocele. At least nine patients underwent two or more surgical operations; one patient had six recurrences over a 15-year period. There were no known deaths from the tumor, but its potentially massive size can result in considerable morbidity and cosmetic deformity. Although previously referred to as active juvenile ossifying fibroma, the term psammomatoid ossifying fibroma for this lesion is more descriptive and has historical precedence.

The mineralized matrix patterns demonstrated in clinical radiographs of primary bone neoplasms and related disorders help to predict matrices, and have diagnostic significance. These radiographic patterns may yield important clues as to the true nature of a lesion, especially when only limited biopsy material is available from extraosseous or nonrepresentative areas. Therefore, in the evaluation of bone tumors and tumor-like conditions, it is of extreme importance to correlate the histologic findings with the radiographic examination and to know precisely the location at which the biopsy material was obtained. Patterns of mineralization may be the only remnants of a pre-existing lesion that has undergone sarcomatous transformation, such as in bone infarcts, enchondromas, or osteochondromas. The pre-eminent item of importance for patient care is the diagnosis of a malignant process. However, failure to appreciate antecedent benign conditions will not contribute toward a better understanding of tumor biology or a determination of those benign lesions that warrant removal or close clinical follow-up. Integration of matrix data with knowledge of the anatomic location of a lesion, the character of its margins, and the periosteal reaction patterns it produces permits prognostication and often, specific diagnosis.

The activated periosteum has a deceptive anatomic constancy amidst change. The change involves the production of matrix and, in the process, proliferation and expenditure of cells. When the demand for a reaction is excessive, nearby extraperiosteal soft tissue serves as a ready source for additional modulating cells, just as it does for fracture callus. The configuration of a periosteal reaction is an index of the nature and intensity of the inciting process.

Double tracking of barium in the sigmoid colon has been associated with granulomatous colitis by some; others consider it a sign of peridiverticulitis. Patients who showed no evidence of inflammatory disease elsewhere in the large intestine were analysed. The pathological diagnosis was diverticulitis in 29 of 35 cases, and granulomatous diverticulitis in only 1. In 5 the underlying process was perforated carcinoma of the sigmoid colon. In those with paracolonic sinus tracts due to peridiverticulitis, pathological study demonstrated tracts extrinsic to the muscularis and usually traceable to a perforated diverticulum. Long-term follow-up disclosed no evidence of subsequent inflammatory bowel disease.