Seng Geok Nicholas Goh

Leiomyomatosis-Like Lymphangioleiomyomatosis of the Colon in a Female with Tuberous Sclerosis

Smooth muscle lesions of the large bowel, excluding the rectum, are generally rare, and diffuse smooth muscle lesions, termed leiomyomatosis, are even rarer. In this report, we document, for the first time, leiomyomatosis-like lymphangioleiomyomatosis (LAM) of the ascending, transverse, and descending colon in association with bilateral renal angiomyolipoma (AML) in a 30-year-old Chinese female with tuberous sclerosis complex (TSC). She presented with protracted constipation for which a colectomy was performed. Histology disclosed multiple confluent nodular CD34 and CD117 negative smooth muscle proliferation within the large bowel wall, whereas the renal biopsy revealed typical features of AML. Interestingly, the epithelioid smooth muscle cells of both the colonic and renal lesions were HMB45 positive, suggesting that leiomyomatosis-like LAM of the colon, pulmonary LAM and AML are closely related entities. The patient remained free of complications for the last five years after surgery. Leiomyomatosis-like LAM of the large bowel probably represents another manifestation of the tendency of TSC to be associated with proliferative lesions.

Solitary fibrous tumour in the deep soft tissue of the neck in a Chinese man

Summary Originally described in the pleura, solitary fibrous tumour (SFT) is now reported in a variety of extrapleural sites. However, description of SFT in the deep soft tissue of the neck is very rare. In this report, we document the neoplasm, deep to the right platsyma muscle but superficial to the deep fascia just above the clavicle, in an otherwise well 50‐year‐old Chinese man. Histological examination of the excised specimen disclosed spindle‐shaped cells disposed in short fascicles as well as randomly in association with areas of varying cellularity, keloidal hyalinisation of the stroma and haemangiopericytoma‐like vessels. The tumour cells were CD34‐, bcl‐2‐ and CD99‐positive. Since histological features may not accurately predict the biological behaviour of this tumour, careful long‐term follow‐up is advocated.

Intravascular lymphomatosis of the lung and liver following eyelid lymphoma in a Chinese man and review of primary pulmonary intravascular lymphomatosis

Summary Intravascular lymphomatosis (IVL) is characterised by an almost exclusive intravascular proliferation of malignant lymphoid cells, with the diagnosis often made only when the illness is in its terminal phase or at autopsy. We detail a case of IVL affecting the lung and liver of a 49‐year‐old Chinese man presenting primarily with lung symptoms and incidental findings of abnormal serum transaminase levels, the antemortem diagnosis being established on transbronchial lung biopsy and percutaneous liver biopsy specimens, respectively. Histology disclosed CD20+ CD5‐ CD10‐ malignant large mononuclear B cells within the lumina of the blood vessels of the affected organs as well as sinusoids of the liver. Significantly, the patient had a history of large B cell lymphoma affecting the eyelid 18 months prior to the angiotropic disease, suggesting a possible link between the more common types of non‐Hodgkins lymphoma and IVL. A brief review of all cases of primary pulmonary intravascular lymphomatosis is also presented.

Pseudodicentric (16;12)(q11;p11.2) in a type AB (mixed) thymoma

Genetic alterations of thymomas are rarely described in the literature. In this study, a previously unreported instance of aberrant karyotypic change consisting of 45,XX,pseu dic(16;12) (q11;p11.2) [cp23]/87-90,idemx2[cp4] in a Masaoka Stage II mixed thymoma or type AB thymoma affecting a 56-year-old Chinese woman is detailed. Abnormalities involving 12p containing important tumor suppressor-like genes have been documented especially in hematological malignancies. Recently, recurrent losses involving 16q, a locus known to harbor several tumor suppressor genes, have been described in type C thymomas (squamous cell carcinoma), suggesting a possible relationship between type AB thymoma and type C thymoma. Whether these genes are involved in the pathogenesis of type AB thymoma remain to be clarified and it is currently unclear if cytogenetic studies may eventually play a role in the classification of thymic tumors.

Role of intraoperative smear cytology in the diagnosis of anaplastic oligodendroglioma. A case report.

BACKGROUND While the intraoperative smear cytology of oligodendroglioma is well documented, the cytologic features of anaplastic oligodendroglioma have been described rarely. CASE A 41-year-old man with a previous history of a brain tumor five years earlier presented with recurrent neurologic symptoms. Radiologic examination revealed a predominantly cystic tumor with solid areas and calcifications arising from the left temporal lobe. Intraoperative smears of the tumor were hypercellular, disclosing loosely cohesive and single cells resembling oligodendrocytes with mitotic activity and moderate anisonucleosis. The background displayed a characteristic vacuolated appearance. Tissue submitted for frozen section showed a tumor with an infiltrative margin with areas of perineuronal satellitosis. CONCLUSION A diagnosis of anaplastic oligodendroglioma can be made intraoperatively with the aid of smear cytology in conjunction with frozen section, assisting intraoperative management.

An unusual cause of granulomatous inflammation: eosinophilic abscess in Langerhans cell histiocytosis.

Eosinophilic abscess inciting a granulomatous response has rarely been reported and appears not to have been described in the setting of a neoplasm. In this report, a case is described where a granulomatous response occurred around eosinophilic abscesses in a patient with Langerhans cell histiocytosis, an association which has not previously been documented. On histology, the excised lymph node showed the presence of eosinophilic abscess and necrosis surrounded by granulomas, which in turn were surrounded by Langerhans cells, a feature confirmed on immunohistochemistry. Although rare, this case highlights the importance of careful examination of eosinophilic abscess with granulomatous inflammation in order to exclude an underlying neoplasm.

Role of FNAC in metastasizing malignant mixed tumor of the external auditory canal: A case report

BACKGROUND No previous report of metastasizing mixed tumor (pleomorphic adenoma) of the external auditory canal (EAC) has been described. CASE A 12-year-old, Chinese girl with a history of mixed tumor of the EAC presented with a locally recurrent, aggressive tumor and metastases to the lung and bone five years later. The primary, locally recurrent and metastatic lung tumor showed epithelial and myoepithelial elements with duct formation, chondromyxoid stroma and mitotic activity in the cellular areas on histology. Fine needle aspiration cytology (FNAC) disclosed the presence of spindle cells blending into chondromyxoid fibrillar ground substance in the recurrent and metastatic lung tumors. CONCLUSION In primary mixed tumor of the EAC, FNAC plays a useful role in the diagnosis of recurrent and metastatic disease. Its ability to identify ominous features, such as increased mitoses in this case, may be limited by sampling. Since cytology and histology cannot reliably prognosticate, long-term follow up of mixed tumor of the EAC after complete excision is advocated.

A 43-year-old chinese man with a retro-orbital mass.

Schwannomas are infrequent intracranial tumors, comprising only 8% of all primary intracranial neoplasms. They are typically located in the cerebellopontine angle region (5). The cellular schwannoma, described by Woodruff in 1981 (8), is considered a variant of schwannoma and comprises about 10% of all schwannomas (5). The most common location of cellular schwannoma is the paravertebral region with the sacral site constituting 64% of all neoplasms (1). The intracranial location accounts for 8% of all cellular schwannomas. The retrobulbar region is an extremely uncommon site for this tumor and to the best our knowledge, our current case forms the fourth case after those described by Casadei et al (1) and Huang et al (4) Cellular schwannoma is generally encapsulated and sometimes associated with a nerve (1). On histology, unlike classical schwannoma, cellular schwannoma discloses a marked increase in cellularity, comprising fascicles of spindle cells which can occasionally be associated with a herringbone or storiform pattern. Compact and hypercellular fascicles recapitulating Antoni-A areas can be identified. Although classic Verocay bodies are seldom identified, there may be occasional suggestion of palisades (1, 2, 4, 7). Antoni-B areas are, however, not prominently featured (1). The spindle cells may exhibit mild nuclear atypia (4, 7). Thick-walled blood vessels usually displayed in classic schwannoma are also present in the cellular variant (1, 4). Microscopic areas of necrosis may be observed in cellular schwannoma, but the geographic necrosis seen in malignant peripheral nerve sheath tumor (MPNST) is absent (1, 3, 7). Mitotic activity usually does not exceed four per 10 high power fields (2–4) although in plexiform cellular schwannoma in childhood, a mitotic index of up to 31 per 10 high power fields has been reported (9). Cellular schwannoma is strongly positive for S100 protein and vimentin (1). GFAP is variably positive (1, 2, 4, 7). The striking feature seen ultrastructurally is the presence of numerous tightly packed intertwined cell processes (1) as identified in our case. Primitive intercellular junctions and cell membranes abutting stroma and covered by well-developed continuous and occasionally duplicated basement membranes, are also present. Luse bodies may be absent. In the retrobulbar region, a diagnosis of meningioma may be considered, as the tumor cells in a cellular schwannoma may form whorls (1). However, the presence of areas resembling Antoni A in association with a negative staining for EMA mitigates against a diagnosis of meningioma. Glial tumors enter the differential diagnosis given the findings of GFAP positivity within the tumor. However, careful discernment of Antoni A-like areas and ultrastructural findings on electron microscopy in conjunction with the clinical and radiological findings favor a diagnosis of cellular schwannoma in our case. Cellular schwannoma may be mistaken for MPNST because of its association with increased cellularity, nuclear atypia, mitotic activity, necrotic foci, bony erosion and tumor recurrence (1, 2, 4, 7). However, a MPNST (3) is usually more cellular, associated usually with a higher degree of anaplasia, lacks the thick walled hyalinized blood vessels and usually demonstrates only focal S-100 positivity on immunohistochemistry. In the orbital region, a solitary fibrous tumor has been confused for a schwannoma (6). While metastases and death have not been described in cellular schwannoma (1, 2, 4, 7), recurrences in incompletely resected cellular schwannoma have been documented, especially in sites where complete tumor resection is difficult to achieve (eg, intraspinal or intracranial) (1, 4). In such instances, mitotic count significantly correlates with the incidence of tumor recurrence (1) and close follow-up is advocated.