Hip and Pelvis Bone Tumors: Can You Make It Simple?

Although it is possible for any osseous tumor or tumorlike lesion to occur in and around the hip and pelvis, there are preferential lesions. Most tumors share many imaging features with those arising elsewhere in the skeletal system, but some may show specific morphological and imaging features. Furthermore, specific criteria and rules of thumb are related to this anatomical area that radiologists should know, which together with the imaging findings and clinical context will lead to a more confident diagnosis.In this article we review the basic anatomical and imaging principles in the hip and pelvis and their diagnostic criteria, describe the most common regional benign and malignant bone tumors and pseudotumors, and highlight their main imaging features and common differential diagnosis while keep this article as relatively simple and straightforward as possible. Soft tissue tumors are beyond the scope of this article.

Relapsing Tumefactive Demyelination: A Case Report

<p><strong>Objective. </strong>We present a case of relapsing tumefactive demyelination in a young female patient, that posed a real diagnostic challenge, with a heterogeneous clinical picture, atypical for multiple sclerosis (MS) presentation, and neuroradiological manifestations with a high suspicion of neoplastic diseases.</p><p><strong>Case Report</strong>. An 18-year old female patient presented to our Neurosurgical Out-patients’ Clinic with symptoms atypical for multiple sclerosis, unremarkable neurological deficit, one tumefactive lesion on MRI, followed by relapse and another two lesions within a period of six months. We decided to perform biopsy of the tumefactive lesion with compressive effect. Serological and clinical data were negative for MS, and the patient did not respond well to corticosteroid therapy. Fresh frozen tumor tissue aroused a strong suspicion of gemistocytic astrocytoma, so total resection was done, but the definitive pathohistological examination confirmed tumefactive demyelination.</p><p><strong>Conclusion</strong>. For clinicians, it is important to consider demyelinating disease in the differential diagnosis of a tumorlike lesion of the central nervous system, in order to avoid invasive and potentially harmful diagnostic procedures, especially in younger patients.</p>

Müllerianosis of the Urinary Bladder: A Rare Tumorlike Lesion

Müllerianosis was first described as a rare entity consisting of an admixture of cervical, tubaric, or endometrial epithelium within the lamina propria and muscularis propria of the urinary bladder. This lesion occurs mainly in the dome or posterior wall of the urinary bladder in women of fertile age. Its clinical presentation is characterized by hematuria, pelvic pain, and dysuria, nonspecific symptoms that are related to the responsiveness of müllerian glands to hormonal stimuli. The major interest of müllerianosis resides in its similarity, from clinical, cytologic, and histologic viewpoints, to more threatening conditions, such as neoplasias. The clinical context and the identification of periglandular endometrial stroma at histologic examination with conventional hematoxylin-eosin stain, as well as the immunohistochemical demonstration of estrogen and progesterone receptors in the glands, are of diagnostic utility in the differential diagnosis. Müllerianosis may be responsive to gonadotropin-releasing hormone agonists. Surgical resection may be justified in the case of clinical symptoms refractory to hormone therapy.

Large occipital aneurysmal bone cyst causing obstructive hydrocephalus in a pediatric patient

Aneurysmal bone cyst (ABC) is an uncommon benign, tumorlike lesion of bone that is usually located in the long bones and spine. On rare occasions, ABCs are found in the bones of the cranial vault and skull base, occasionally causing mass effect and cranial nerve findings. In this report the authors detail the case of a patient who presented with incidentally discovered hydrocephalus due to a large ABC of the occipital bone that produced mass effect and obstruction of CSF. The diagnosis, imaging findings, and surgical management of this interesting and rare case are discussed.

Cutaneous Neoplasms in Pet Rabbits: A Retrospective Study

Over a 16-year period, 190 tumors and tumorlike lesions from 179 pet rabbits were submitted for histopathologic examination. A total of 23 different tumor types and 1 tumorlike lesion were diagnosed. The most common diagnoses were trichoblastoma, collagenous hamartoma, and Shope fibroma. Viral-induced tumors were Shope fibroma (19) and Shope papilloma (2). Common nonviral epithelial tumors included trichoblastoma (59), squamous cell carcinoma (5), squamous papilloma (4), trichoepithelioma (3), and apocrine carcinoma (3). Common mesenchymal tumors were lipoma (10), liposarcoma (3), myxosarcoma (9), malignant peripheral nerve sheath tumor (8), fibrosarcoma (7), and leiomyosarcoma (4). Malignant melanoma was diagnosed in 8 rabbits. Collagenous hamartomas were diagnosed in 26 rabbits. Mesenchymal proliferations occurred significantly more often in male rabbits than in females. Collagenous hamartomas and myxosarcomas occurred exclusively in male animals, and 3 rabbits had multiple collagenous hamartomas. Immunohistochemistry was applied in cases in which a definite diagnosis could not be reached on hematoxylin and eosin slides. Follow-up information was received in 19 cases. Carcinomas recurred (2 of 3) or metastasized (1 of 3), whereas sarcomas frequently recurred (7 of 12). One malignant melanoma (1 of 3) and one poorly differentiated round cell neoplasm recurred (1 of 1). This is the first comprehensive retrospective analysis on skin neoplasia in pet rabbits.