Nodular histiocytic/mesothelial hyperplasia: a lesion potentially mistaken for a neoplasm in transbronchial biopsy.

This report describes two examples of nodular histiocytic/ mesothelial hyperplasia as seen in transbronchial biopsy that initially led to serious consideration of neuroendocrine neoplasm or meningioma. The biopsies showed nodular collections of cohesive polygonal or round cells with ovoid or deeply grooved nuclei and a moderate amount of finely granular cytoplasm. Nuclear pleomorphism was mild. Immunohistochemical studies showed few cells staining for cytokeratin and the mesothelial marker HBME-1, whereas most cells were decorated by the histiocytic marker PG-M1 (CD68). This lesion appears to be identical to nodular mesothelial hyperplasia as described in hernia sacs and mesothelial/monocytic incidental cardiac excrescences, and we propose modifying the designation to "nodular histiocytic/mesothelial hyperplasia" to take into account the marked predominance of histiocytes over mesothelial cells. The clues to recognition of the true nature of the lesion are clinicopathologic correlation and identification of strips of low cuboidal (mesothelial) cells in the vicinity, and the diagnosis can be further confirmed by immunohistochemical staining. Nodular histiocytic/mesothelial hyperplasia probably results from irritation to the mesothelial lining by various causes leading to focal aggregation of histiocytes within retraction pockets or crevices of the serosal cavity.

Biliary adenofibroma. A heretofore unrecognized benign biliary tumor of the liver.

Benign biliary tumors of the liver are uncommon. In this report, we describe a distinctive biliary tumor of 7-cm diameter occurring in the right lobe of the liver of a 74-year-old Chinese woman. The lesion, characterized by a complex tubulocystic nonmucin secreting biliary epithelial and an abundant fibroblastic stromal components, is distinct from other well-recognized biliary lesions. A number of unusual features are focally present, namely, intraluminal bile concretions, apocrine-like epithelial change, acute inflammation, and granuloma. The tumor shows a striking resemblance to Meyenburg's complex (MC), but the large size of the lesion and the absence of any typical MC in the background liver are exceptional for the latter. Its expansile growth, possession of mitoses, and foci of epithelial tufting and cellular atypia favor a neoplastic process. Previous reported cases of adenomatous neoplastic transformation of MC are dissimilar. We therefore conclude that this is a hitherto unrecognized biliary tumor that may be yet another neoplastic form of MC and propose the designation biliary adenofibroma. The course appears benign, but malignant epithelial transformation may supervene if the lesion is left untreated.

Hepatocellular carcinoma metastasizing to the brain and orbit: report of three cases.

Hepatocellular carcinoma rarely metastasizes to the brain or orbit. We report 3 clinically manifest examples, one of which occurred in a 13-yr-old boy. In 2 cases the intracranial metastasis was the initial presenting lesion. The 2 cases of brain metastasis both presented with intracerebral hemorrhage. Light microscopic examination of these tumors revealed a trabecular hepatocellular carcinoma of Edmondson grade II with focal hemorrhage and necrosis. Their immunohistochemical profile was identical to that described for primary hepatocellular carcinoma. The differential diagnosis from other intracranial metastatic tumors is discussed.

Primary multifocal leptomeningeal gliomatosis.

A 23-year-old female university student was presented with recent onset of non-specific headache and dizziness. She had no neurological deficit on neurological examination and magnetic resonance imaging of the brain revealed diffuse enhancement in the basal cisterns and cerebral sulci. She was treated as tuberculous meningitis but she did not improve and developed respiratory arrest. Autopsy showed primary multifocal leptomeningeal gliomatosis.

Colloid adenocarcinoma of the urethra associated with mucosal in situ carcinoma.

Adenocarcinoma is a rarity among the primary urethral carcinomas. It usually exhibits a papillary or glandular pattern and is often believed to arise from the mucosal glands. We report a unique case showing the histologic features of colloid adenocarcinoma that appears to have evolved from carcinoma in situ of the urethral epithelium.

Cribriform variant of papillary thyroid carcinoma.

We report a case of papillary carcinoma of the thyroid exhibiting unusual cribriform structures. The thyroid origin of the tumor was confirmed by positive immunostaining for thyroglobulin.

Merosin-deficient congenital muscular dystrophy in two siblings.

Congenital muscular dystrophies are a group of heterogeneous inherited autosomal recessive disorders. The so-called 'pure' or 'occidental' form is further divided into merosin-positive and merosin-negative subgroups. Merosin is also expressed in the nervous system and its deficiency could affect development of the nervous system. The authors report two siblings with merosin-negative congenital muscular dystrophy. The clinical picture, biopsy findings, and abnormalities as detected by the magnetic resonance imaging of the two patients are presented.

Creutzfeldt-Jakob disease in Hong Kong.

Two elderly patients presented with rapidly progressive dementia and their electroencephalograms showed periodic discharges. Creutzfeldt-Jakob disease was pathologically confirmed in one of the patients. Striking clinical features and characteristic electroencephalograms should prompt the clinical diagnosis in most patients.

Cutaneous cryptococcosis--primary versus secondary disease. Report of two cases with review of literature.

The clinical, immunological, and pathological features of solitary cutaneous cryptococcosis in two apparently healthy Chinese adults are reported. In patient 1, regional cryptococcal lymphadenopathy also occurred. Both patients showed lymphopenia with a proportionate decrease in T-helper and T-suppressor cells. Both skin and lymph node biopsies showed granulomatous inflammation and the presence of cryptococcus. A chancriform syndrome developed in patient 1, indicating primary cutaneous cryptococcosis. Chancriform syndrome is rare in cryptococcal skin infection, probably due to immunosuppression in susceptible patients. In patient 2, the deep dermal and subcutaneous inflammatory involvement and anatomic location of the lesion on the upper medial thigh are supportive of secondary skin disease. Unless negated by a reliable history, the following features are indicative of secondary disease: inflammation centered in deep dermis or subcutaneous fat, lesion on covered parts of body, and multifocal skin lesions. Some cases remain unclassifiable. In practice the distinction between primary and secondary cutaneous cryptococcal disease is not essential because less toxic, effective antifungal drugs are now available.

Alveolar rhabdomyosarcoma of the cervix.

BACKGROUND: Alveolar rhabdomyosarcoma (RMS) has a high risk for local and distal failure. Multimodal management of a patient with alveolar RMS of the cervix uteri is outlined. CASE: A 39-year-old woman suffered from alveolar RMS of the cervix without involvement of uterus and parametrium. She was treated with total hysterectomy and left salpingo-oophorectomy. Systemic chemotherapy and pelvic irradiation were also offered. She remains in clinical remission 3 years after presentation. CONCLUSION: Postoperative chemotherapy and irradiation could be effective treatments for alveolar rhabdomyosarcoma of the cervix in adult patients.

Acute fulminant neuropathy in a patient with Churg-Strauss syndrome.

We report a patient with an acute neuropathy initially mimicking Guillain-Barré syndrome, both clinically and electrophysiologically. Persistent eosinophilia, positive antineutrophil cytoplasmic antibody and eosinophilic vasculitis in sural nerve biopsy later confirmed Churg-Strauss syndrome. Since vasculitic neuropathy can present in an acute and fulminant form, the role of early antibody testing and sural nerve biopsy in atypical cases of acute neuropathy is emphasized.

Granulomatous slack skin.

Granulomatous slack skin is an extremely uncommon form of cutaneous T-cell lymphoma. We report a case occurring in a 29-year-old man, who had generalized, progressive skin lesions evolving to nodular swellings and folds in the flexural regions, and peripheral blood and marrow involvement. The biopsies were initially misinterpreted as xanthogranuloma or granulomatous inflammation. Histologically, the entire dermis and subcutis was infiltrated by non-necrotizing granulomas comprising mononuclear histiocytes, multinucleated giant cells and small lymphoid cells with irregularly folded nuclei, associated with loss of elastic fibres. The small lymphoid cells showed focal epidermotropism. Immunohistochemical studies showed that they were of T-lineage (CD3+, CD43+, CD45RO+). The multinucleated giant cells, which showed reactivity with the histiocytic markers CD68 and Mac387, were highlighted by intense, thick membrane staining with CD45, CD43 and CD45RO. Ultrastructurally, they exhibited features of macrophages with numerous surface villous processes and lysosomes. Greater awareness of this entity may facilitate more prompt and accurate diagnosis, obviating a futile search for a non-existent infective aetiology.