Cesarean Section Scar Diverticulum

A sagittal US scan of the uterus shows a cystic lesion in the anterior wall of the lower uterine segment. The patient reported prior cesarean section

Facts:

• Defect within the lower uterine cavity in patients with history of cesarean section in expected location of a hysterectomy incision
• Based on a study utilizing hysterosalpingograms, 60% of women with prior C-section had this anatomic defect
• Knowledge of this anatomic defect avoids misdiagnosing it as other pathology
• Often benign clinical significance. Some reports of ectopic scar pregnancy and abnormal uterine bleeding associated with this pathology

Imaging Appearance

• Focal outpouching (most common feature) and thin linear defect
• Location: lower uterine segment (most common) > uterine isthmus, upper endocervical canal

Imaging Mimics

• Prominent cervical glands (tubular, symmetric structure from both walls of endocervical canal)
• Postmyomectomy diverticula (unilateral, from site of resection, correlated with surgical history and location of diverticula)
• Gartner's duct cyst (long, tubular structure parallel to uterine cavity)
• Adenomyosis (location of defect anywhere along uterine cavity)

Reference

Surapaneni K, Silberzweig JE. Cesarean section scar diverticulum: appearance on hysterosalpingography. AJR 2008;190:870-4

Lucencies and Cavitation in Bronchioloalveolar Carcinoma

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The chest radiograph shows an ill-defined focal opacity in the left lower lung zone.

Coronal-reformatted CT image done a few days after the chest radiograph reveals an irregular-shaped mass with internal lucencies that represent air bronchiologram and cavity. Desmoplastic reaction is also visualized.

Facts: BAC

• Well-differentiated adenocarcinoma of the lung
• Polymorphism
• Lepidic growth meaning spread of neoplastic cells in peripheral air space without destroying lung architecture
• On CT, it can be a nodule, mass, consolidation (segmental or lobar), multi centric or diffuse disease

Facts: Radiolucencies in BAC

• Important CT feature is internal radiolucencies but this is overlapping with other diseases
• Lucencies can represent air bronchiologram, bubbles of pseudocavitation, cavitation, serpentine, alveologram or thin-walled cystic lesions
• Bubbly lucencies or pseudocavitation is believed to be non-involved lobules, paracicatricial emphysema and fibrosis with honeycombing and localized bronchiectasis.

Our case: BAC with air bronchiologram and cavity.

Reference:

Gaeta M, et al. Radiolucencies and cavitation in bronchioloalveolar carcinoma: CT-pathologic correlation. Eur Radiol 1999;9:55-59.

Is Plain Radiography Sensitive Enough to Detect Pneumoperitoneum?

An upright chest radiograph shows a large amount of pneumoperitoneum under the right hemidiaphragm of a patient who has peptic ulcer perforation found at surgery.

Facts: Pneumoperitoneum & GI perforation

• Common
• Requires a breach through all layers of hollow viscus that would allow escape of intraluminal content into the peritoneal cavity
• Results in peritonitis, either localized or generalized

Detectability Rate of Imaging

• Plain radiography sensitivity ranges from 50% to 98% depending on the technique (upright chest, upright abdomen, left lateral decubitus, supine abdomen) and additional postural maneuver
• Recent study of 1,723 patients with GI perforation shows that radiography (either upright chest, upright abdomen or both) has positivity rate of almost 90%. 10% of radiographs did not show free air despite patients having GI perforation. Highest positivity rate was seen with gastric and duodenal perforation (94%), but lowest with appendiceal perforation (7%)

Reference:

Bansal J, Jenaw RK, Rao J, et al. Effectiveness of plain radiography in diagnosing hollow viscus perforation: study of 1,723 patients of perforation peritonitis. Emerg Radiol 2011 December.

Calcaneal Hemangioendothelioma

Authors: Bahri Nandini, M.D. and Sanjay B. Nathani, M.D. (Radiodiagnosis)

Editor: Rathachai Kaewlai, M.D.

Ankle radiograph shows a well defined lytic lesion with few septa in the anterior part of the calcaneus. There is cortical destruction at the medial and superior cortex of the calcaneus.

Sagittal PDT2W and coronal T1W MR images of the hindfoot show a lobulated mass with internal septa in the anterior part of the calcaneus with etension into the adjacent myofascial planes. The lesion is hypointense on T1W and hyperintense on T2W sequences.

Quick Facts:

• Hemangioendothelioma and angiosarcoma are a group of primary malignant vascular tumors of the bone, which are extremely rare
• Common locations: femur, tibia, pelvis and vertebra
• Age group: between 4th and 5th decade
• Imaging appearance: lytic lesion without sclerotic border, multilocular, bone expansion and laminated periosteal reaction
• Common differential diagnosis = aneurysmal bone cyst, simple bone cyst
  

The Case

• A 50 years old female presented with pain and swelling at left foot with no history of trauma. On clinical examination local tenderness at heal was present.
• Radiograph taken in oblique (fig 1) positions, showed a well defined, lobulated lytic lesion with a few internal septa in the anterior part of Calcaneum. The lesion extends and breaches the medial and superior cortex of calcaneum
• MRI study of foot and ankle using 1.5T Siemens Magnetom Essenza machine, which included T1, T2, PD and T2 fat suppressed axial, sagittal and coronal sequences were performed. On PDW sagittal and T1 coronal images the lesion appears well defined, lobulated , with few internal septas in the anteroinferior part of calcaneum and breaches the medial and superior cortex and involves the adjacent myofascial planes. The lesion is hyperintense on PDW images [figure 2 A] and hypointense in T1W coronal images [figure 2 B] Tibiotalar joint shows minimal joint effusion.
• On histopathological examination of the material obtained after intraoperative curettage of calcaneum findings were in favor of tumor of vascular origin.
• On the basis of the clinical, radiological and histopathological findings, presumptive diagnosis of Calcaneal Hemangioendothelioma was considered.

Discussion

• Hemangioendothelial sarcoma includes hemangioendothelioma and angiosarcoma, which encompasses a group of primary malignant vascular tumors in bone that vary from the malignant capillary and cavernous blood vessel formation to the proliferative endothelial sarcomas. Hemangioendothelioma is a tumor of blood vessels, in which endothelial cells are seen as predominant cell
• Primary malignant vascular tumors in bone are extremely rare(less than 1% of all bone tumors). It can occur in all age groups; however most of the patients are between 4^th and 5^th decades of life. Most commonly affected bone is Femur (16%), followed by Tibia(14%), pelvis(12%), vertebra(10%). Other rare sites are foot, hand, forearm bones and clavicle. The patient may not experience any specific symptoms or signs. Patient may present with Pain or occasionally swelling. Hemangioendothelioma shows multicentricity of lesions in the bones of the same extremity. On Radiographs, the solitary lesion is well circumscribed, lytic with no surrounding sclerosis or matrix mineralization, which shows internal septa which may be scant or incomplete. Occasionally it may show multilocular appearance. The tumor causes expansion, thinning and erosion of the cortex and often associated with a mild laminated periosteal reaction.
• On MR imaging, the lesion appears well defined, multilocular which is hyperintense on T2W and PDW images and hypointense on T1W images with internal septa. The lesion involves the surrounding soft tissue and involvement of multiple bones can occur.
• The etiology of unicameral bone cysts of the calcaneum is an enigma, just as it is with these lesions in other bones. Popular theories regarding the origin of bone cysts have been related to the long bones and the juxtaposition of the cyst to the growth plate
• Most commonly considered differential diagnoses are Simple Bone Cyst, Aneurysmal Bone Cyst. That can be differentiated by moth eaten erosion pattern and irregular margins of Hemangioendothelial sarcoma.

This case is a 50-year-old female with pathological findings of a tumor of vascular origin.

References:

1. Ackerman LV, Spujat HJ. Tumors of bones and cartilage. Atlas of tumor pathology. Armed Forces Institute of Pathology, Washington, DC, 1962

2. Jaffe HL, Lichtenstein L. Solitary unicameral bone cyst with emphasis on the roentgen picture. Arch Surg 1942;44:1004-1025

3. Smith RW, Smith CF. Solitary unicameral bone cyst of the calcaneum: a review of twenty cases. J Bone Joint Surg Am 1974;56:49-56.

About Authors: Drs. Nandini and Nathani work for the Department of Radiodiagnosis, G.G. Hospital, Jamnagar, Gujarat in India. Their work does not have any support for the work in the form of grants, equipments or drugs.