Leiomyoma is a smooth muscle tumour that can arise in any part of the body especially the uterus. Even though it is traditionally linked with hormonal influence, it can also develop in extrauterine organs with a slight female predominance. It is indistinguishable with gastrointestinal stromal tumour (GIST) histologically. We report a case of a 30-year-old gentleman who presented with a huge painful mass in the right iliac fossa. Computed tomography revealed a 10 × 10 cm homogeneous mass arising from the terminal ileum; he subsequently underwent an open right hemicolectomy. Histology showed a well-circumscribed lesion composed of interlacing bundles of smooth muscle fibres of the submucosa with positive smooth muscle actin and H-Caldesmon stains but negative for DOG-1 and CD117 (c-kit) stains which were consistent with leiomyoma. Despite its rarity, this hormone-related tumour needs to be considered regardless of gender. Immunohistochemistry is paramount as it is histologically identical to GIST.
Intramuscular shoulder angiomyolipomas are very rare. We report a case in a 22-year-old male with a well circumscribed lesion located on the back of the shoulder. This lesion, differs from renal angiomyolipoma in terms of non-association with tuberous sclerosis, circumscription and male predominance. Another characteristic feature is the absence of epithelioid cells. Differential diagnosis includes lipoma, angiolipoma, angioleiomyoma, hemangioma, myolipoma and liposarcoma. It is distinguished from the above mentioned entities by the presence of a combination of thick-walled blood vessels, smooth muscle and fat.
Intramuscular shoulder angiomyolipomas are very rare. We report a case in a 22-year-old male with a well circumscribed lesion located on the back of the shoulder. This lesion, differs from renal angiomyolipoma in terms of non-association with tuberous sclerosis, circumscription and male predominance. Another characteristic feature is the absence of epithelioid cells. Differential diagnosis includes lipoma, angiolipoma, angioleiomyoma, hemangioma, myolipoma and liposarcoma. It is distinguished from the above mentioned entities by the presence of a combination of thick-walled blood vessels, smooth muscle and fat.
AIM: To study the clinical features, histology and immunohistochemical properties of gastrointestinal stromal tumours (GISTs); and establish any parameters that can help prognosticate the malignant potential.
METHODS: Twenty-six patients with GISTs who were seen in Sultanah Aminah Hospital Johor, Malaysia from 1999 to 2003 were selected for study. Patient, clinical characteristics and outcome based on surgical records were analysed. Tumour variables (tumour size, cellularity, mitotic count, necrosis and haemorrhage) were compared between very low to low risk groups and intermediate to high risk groups. The immunohistochemical properties of GISTs were also studied.
RESULTS: Patients with GISTs presented mainly with pain, palpable mass or gastrointestinal tract bleeding. The tumours were seen in stomach (50%) followed by small intestine (38.5%) and rectum (11.5%). In the period of study, six patients had metastasis, mainly in the liver or peritoneum. Immunoreactivity for CD117, CD34, vimentin, S100, neuron specific enolase, alpha-smooth-muscle-actin and desmin were observed in 100%, 76.9%, 61.5%, 46.1%, 80.8%, 11.5% and 0% of tumours respectively. The behaviour of GISTs was largely dependent on tumour size and number of mitosis. Necrosis and haemorrhage were seen in tumours with high risk potential.
Lymphangioleiomyomatosis (LAM) is a rare disease. The reported prevalence is around one per million in the West but the exact prevalence in Asia is unknown. It affects primarily young women of reproductive age, with a mean age of onset at 34 years. The disease is characterised by an abnormal proliferation of smooth muscle-like cells that grow over a course of time to obstruct airways, lymphatic and blood vessels. We report a case of LAM in a young woman who presented with a spontaneous pneumothorax. Computed tomography scan of the thorax and abdomen showed homogenous thin-walled cystic lesions with normal intervening lung parenchyma and multiple lesions in her kidneys with Hounsfield units similar to that of fat.
We investigated the biomechanical relationship between intraluminal pressure within small mesenteric resistance arteries, oxidant activation of PKG, Ca2+ sparks, and BK channel vasoregulation. Mesenteric resistance arteries from wild type (WT) and genetically modified mice with PKG resistance to oxidative activation were studied using wire and pressure myography. Ca2+ sparks and Ca2+ transients within vascular smooth muscle cells of intact arteries were characterized using high-speed confocal microscopy of intact arteries. Arteries were studied under conditions of varying intraluminal pressure and oxidation. Intraluminal pressure specifically, rather than the generic stretch of the artery, was necessary to activate the oxidative pathway. We demonstrated a graded step activation profile for the generation of Ca2+ sparks and also a functional "ceiling" for this pressure --sensitive oxidative pathway. During steady state pressure - induced constriction, any additional Ca2+ sensitive-K+ channel functional availability was independent of oxidant activated PKG. There was an increase in the amplitude, but not the Area under the Curve (AUC) of the caffeine-induced Ca2+ transient in pressurized arteries from mice with oxidant-resistant PKG compared with wild type. Overall, we surmise that intraluminal pressure within resistance arteries controls Ca2+ spark vasoregulation through a tightly controlled pathway with a graded onset switch. The pathway, underpinned by oxidant activation of PKG, cannot be further boosted by additional pressure or oxidation once active. We propose that these restrictive characteristics of pressure-induced Ca2+ spark vasoregulation confer stability for the artery in order to provide a constant flow independent of additional pressure fluctuations or exogenous oxidants.