Metastatic pulmonary calcification is a consequence of calcium deposition in the normal pulmonary parenchyma, secondary to abnormal calcium metabolism. The most characteristic radiological manifestation is poorly defined nodular opacities that are mainly seen in the upper lung zone. The aim of this report is to describe the CT and MRI findings observed in two patients with metastatic pulmonary calcification. The disease may present in CT as consolidations with calcification, and with a high lesion/muscle signal intensity ratio on T1 weighted imaging without contrast in MRI. The high signal on T1 weighted imaging probably occurs because the low calcium concentration of the lesion changes the surface effects of diamagnetic calcium particles, causing T1 shortening of water protons. MRI is a good option for characterising calcium accumulation caused by a metabolic disorder.

The presence of the appendix within a femoral hernia is rare. It was first described by the French surgeon Jacques Croissant de Garengeot in 1731. This phenomenon accounts for 0.8–1% of all femoral hernias. Acute appendicitis occurring within a femoral hernia is even rarer and is difficult to diagnose pre-operatively. This type of hernia is termed a de Garengeot hernia. The ultrasonographic and CT imaging features of de Garengeot hernias have been described previously. We report a case of a 57-year-old female who presented with a painful right-sided groin mass. She underwent MRI of the inguinal region, which successfully diagnosed this rare hernia pre-operatively. To our knowledge, this is the first description of a de Garengeot hernia diagnosed using MRI.

Hyperdense renal cysts, a common condition in autosomal dominant polycystic kidney disease, may be induced by haemorrhage into the cysts. However, hyperdense renal cysts resulting from retention of contrast material after intravenous injection is extremely uncommon because the intravenous administration of contrast material does not induce an increase in the attenuation of renal cysts. We report a case of retention of iodinated contrast material within renal cysts in a patient with autosomal dominant polycystic kidney disease.

We describe the use of contrast-enhanced ultrasound as an additional imaging technique during an ultrasound examination of a traumatised testis, allowing for confident testicular preserving surgery to be performed.

We present the case of a 79-year-old female with symptomatic cavernous haemangioma of the liver. The patient had experienced progressive right lateral abdominal pain for years despite increased painkiller use. Surgical resection or transarterial embolisation was not recommended because of the patient’s age, cardiovascular comorbidities and large tumour size. Therefore, the patient was treated with 3-dimensional conformal radiotherapy (RT) with a total dose of 30 Gy in 15 fractions. Following RT, the painkillers were tapered from the third month, and complete symptomatic remission was achieved after the ninth month. The measured tumour volume from serial images pre-RT and 3, 9 and 15 months post-RT was 400 ml, 372 ml, 185 ml and 140 ml, respectively. The most dramatic volumetric reduction was found between 3 and 9 months post-RT, whereas the change before or after this period was minimal. The time course of the radiological volumetric changes correlated with that of the clinical symptoms. In addition, the observed vascular changes on serial imaging studies were consistent with the assumed radiobiological effects after fractionated RT.

Erdheim–Chester disease (ECD) is a rare non-Langerhans cell histiocytosis. We present a case of a 56-year-old male with ECD. As time progressed, involvement of the orbital fossa, cranial convexity, spinal cord, brain stem, thyroid, lung, retroperitoneum, lower extremity bones and skin were found. Previously reported cases reveal the frequency of ECD with spinal cord involvement is rare. Although this was a presumed diagnosis based on other lesions, our case is the first in which both intramedullary and epidural masses are present.

A nerve transfer or neurotisation procedure is performed to repair damaged nerves, in particular those of the brachial plexus following an avulsion injury. An intercostal to phrenic nerve transfer to re-innervate the diaphragm in patients with high cervical spine injury has also been reported in the literature. We present the imaging finding in a 65-year-old female who had an intercostal nerve transfer for a damaged phrenic nerve following a resection for a non-small cell lung carcinoma.

We report an unusual case of intracranial extracerebral neuroglial heterotopia (IENH) presenting with parapharyngeal extension. Neuroglial heterotopias are rarely reported pre-natally and, to our knowledge, there are no reported cases presenting pre-natal imaging findings of IENH with parapharyngeal extension. Because pre- and post-natal imaging studies are essential to diagnose IENH and plan surgical treatment, radiologists should be familiar with this rare condition.

Biliary cystadenomas are predominately benign tumours that have a low malignant potential. We present a case of a 30-year-old female with a histopathological confirmation of a biliary cystadenoma following resection. The diagnosis was made pre-operatively by MRI using the hepatocyte-specific contrast agent gadobenate dimeglumine (Gd-BOPTA) (MultiHance; Bracco Diagnostics Inc., Princeton, NJ). At the biliary excretory phase, delayed phase images demonstrated communication between the multilocular cystic mass and the biliary tree, which helped to confirm the diagnosis of biliary cystadenoma. This highlights the beneficial use of hepatocyte-specific agents for their dual function as an extracellular agent and a hepatobiliary agent.

A 58-year-old female who presented with a lower gastrointestinal bleed was referred for an 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT after a colonoscopy revealed a submucosal mass in the ascending colon. The PET/CT confirmed the presence of an FDG-avid mass in the ascending colon with no other FDG-avid abnormalities. Dual time-point imaging was performed and showed a significant increase in FDG uptake in the mass, which raised strong suspicion of a colon malignancy. Although an initial biopsy of the mass did not show evidence of neoplasia, a decision was made to proceed with a right hemicolectomy based on high clinical and imaging suspicion of malignancy. Histological evaluation of the hemicolectomy revealed a benign colon desmoid tumour.

Gastric haemolymphangioma is a very rare benign tumour. Pathologically, it is composed of lymphatic vessels and blood vessels. Only a few cases of haemolymphangioma have been reported in the literature so far, all of which developed at sites other than the stomach. The authors believe that a haemolymphangioma occurring in the stomach has not been previously reported. The patient was a healthy 68-year-old male who had felt light epigastric discomfort for 3 months. A CT scan and a gastrofiberscope examination revealed a well-demarcated mass on the posterior wall of the stomach near the lesser curvature. The mass was successfully removed by surgery. During the 18-month follow-up period, the patient was asymptomatic with no recurrence. In this case report, we discuss the imaging findings as well as the pathological features of this unusual case, with a review of the related literature.

Persistence of foetal anastomoses between carotid and vertebrobasilar arteries is well recognised, but their bilateral presence is rare. We report a case of bilateral persistent hypoglossal arteries. Absence of bilateral vertebral arteries was incidentally noted on neck ultrasound examination. Subsequent MRI confirmed this and revealed persistent hypoglossal arteries that arose bilaterally from the cervical internal carotid artery, entered the cranium through the hypoglossal canal and joined the lower portion of the basilar artery.

We report a case of early-stage malignant peripheral nerve sheath tumour (MPNST) found in a solitary neurofibroma, and its CT and MRI findings. A 19-year-old male with no known history of a neurofibromatosis presented with a painless swelling in the left forearm. CT and MRI scans showed a well-circumscribed, intermuscular mass, which was 6.0 cm in diameter and contained a strongly enhanced 1.0 cm nodular structure with surrounding oedema. Peripheral nerve continuity with the mass was not seen. Histological evaluation proved the nodular structure was an MPNST component completely surrounded by neurofibroma. Following an excisional biopsy with wide margins, the patient was followed up for a year without treatment and no recurrence was observed.

Primary peritoneal serous borderline tumour (PPSBT) is a rare epithelial neoplasm which is histologically identical to serous borderline tumour of the ovary. PPSBT is distinguishable from primary peritoneal serous carcinoma because the tumour cells do not invade the underlying tissue and affected patients have a good prognosis. We report the CT findings of surgically proven PPSBT in which multiple peritoneal cysts were seen. Although rare, PPSBT should be considered in the differential diagnosis of primary peritoneal tumours. Since the prognosis of the disease is good, conservation of the uterus and ovaries should be a consideration in young female patients during surgery.

Diprosopus is the rarest form of conjoined twinning. This anomaly is characterised by craniofacial duplication to varying degrees and is associated with anomalies of the central nervous, cardiac, respiratory and musculoskeletal systems. We present an infant characterised as diprosopus tetraophthalmus who underwent post-mortem CT, which served as a highly useful complement to autopsy.

We report a peculiar case of recurrent hyperparathyroidism caused by hyperplasia of a forearm graft implanted following a total parathyroidectomy in a 38-year-old patient with chronic renal failure. The forearm graft hyperplasia was detected using 99Tcm-sestamibi scanning, which identified hyperplastic transplanted parathyroid tissue in the forearm of the patient. During the initial surgery, the surgeon failed to mark the parathyroid tissue with sutures or clips to facilitate locating it. Therefore, we referred the patient for radioguided surgery. This surgical procedure allowed us to locate and completely remove the hyperfunctioning transplanted parathyroid tissue.

We report a case of calcifying epithelial odontogenic tumour (CEOT), also known as a Pindborg tumour, with local aggressive behaviour. CT imaging showed a large expansile bone-forming lesion in the mandible, which showed the exact extent and nature of the lesion. We briefly discuss the imaging features of CEOT and the relevant literature.

The differential diagnosis for intense hypermetabolic mediastinal lesions on positron emission tomography (PET) could benefit from the combined morphological and metabolic information present in a fluorodeoxyglucose (FDG) PET/CT study. We report a case of an infected tracheal diverticulum mimicking an FDG-avid malignancy in a patient with a history of chronic lymphoproliferative disease. We review the literature for a systematic approach in the differential diagnosis of cystic mediastinal lesions. The embryological development of the normal tracheobronchial tree is reviewed, followed by a presentation of various congenital and acquired mediastinal lesions. The characteristic CT findings are described for each lesion and the avidity for FDG on PET is mentioned when references are available. This case emphasises that complicated benign processes should be considered in the differential diagnosis of an FDG-avid mediastinal lesion, even in subgroups of patients with significant risk factors for malignancy.

A 53-year-old male with a remote history of colon adenocarcinoma presented with weakness, severe anaemia and an actively bleeding ulcerated lesion in the stomach. An 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT showed FDG-avid masses in the stomach and mesentery, which were biopsied to reveal an unsuspected diagnosis of plasmacytoma. The original colon tumour pathology was identical and this prompted its re-evaluation to a primary colon plasmacytoma. The patient was treated with chemotherapy and a follow-up PET/CT scan showed complete resolution of the gastric and mesenteric masses. 18F-FDG PET/CT is useful in the restaging and follow-up of this very rare extramedullary plasmacytoma.

A liver abscess is a feared and potentially fatal complication following transarterial chemoembolisation (TACE) and radiofrequency ablation (RFA) of liver tumours. Iatrogenic bilio-enteric communications, such as bilio-enteric anastomosis, sphincterotomy and biliary stents, are considered major risk factors and are due to bacterial colonisation of the biliary tree with enteric flora. Naturally occurring spontaneous cholecysto-enteric fistula poses a similar risk as its iatrogenic counterparts but is rarely described in the literature. We present a case where abscess formation complicated a combined TACE and RFA in an unrecognised cholecystocolic fistula.

Acinar cell carcinoma of the pancreas is a rare malignant tumour developing from acinar cells, accounting for approximately 1% of pancreatic exocrine tumours. We experienced a case of an acinar cell carcinoma with fatty change. To the best of our knowledge, this is the first case report of an acinar cell carcinoma with fatty change in the clinical literature.