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Articles in the COTM Category


[1 Dec 2015 | Comments Off on December 2015: A 74 year old woman with abdominal pain | 3,185 views]
December 2015: A 74 year old woman with abdominal pain

History: 74-year-old gravida 1, para 1 female with a history of hysterectomy and bilateral salpingoopherectomy for severe pelvic endometriosis who presented with abdominal pain. A CT scan demonstrated a 6 cm pelvic mass lying between the bladder and rectum. Fecal occult blood test was positive. The patient underwent attempted resection of the pelvic mass, as well as a sigmoid colon resection.

Gross examination of the resection specimens demonstrated a 10 cm mass that is adherent to the sigmoid colon mass. … More


[1 Aug 2015 | Comments Off on August 2015: A five year old girl with a cardiac conduction problem | 1,451 views]
August 2015: A five year old girl with a cardiac conduction problem

History: A 5-year-old girl presented with cardiac conduction problem. Workup revealed a mass in the right atrium.

Microscopically, the mass consisted of enlarged myocytes with abundant, vacuolated or clear cytoplasm (Fig. 1). At higher magnification, the tumor cells had strands of cytoplasmic myofibrils radiating from the central nucleus to the cell periphery forming so-called “spider cells” (Fig. 2). Cross striations were commonly seen (Fig. 3). Neither necrosis nor mitotic figures were present.

Diagnosis: Rhabdomyoma … More


[1 Jun 2015 | No Comment | 2,986 views]
June 2015: A man with a 2.3 cm nodule on the right shin

History: A 37-year-old man presented with a well circumscribed, unencapsulated, bluish pink 2.3 x 2.3 cm nodule on his right shin. A 2.0 x 2.0 cm shave biopsy was taken (Fig. 1).

Microscopically, the tumor was dermal-based and involved adnexal structures. It consisted of disorganized collagenous fibers (Fig. 2) admixed with scattered hyperchromatic pleomorphic cells. Myxoid stromal change and storiform patterns were also seen (Fig. 3).

The pleomorphic cells showed enlarged, spindled to stellate-shaped … More


[1 May 2015 | No Comment | 2,038 views]
May 2015: An adult male with a subcutaneous soft tissue mass involving a heel

History: A painful, one cm nodule was found the subcutaneous tissue of the right heel of an adult male. Radiographs showed it to be ill-defined and radio-opaque. The nearest bone was the calcaneus, but it was not involved. There was no history of trauma.

The lesion, at low magnification, consisted of an admixture of adipose tissue, osteoid, trabecular mature bone, and fibrous stroma (Figs. 1, 2). Prominent osteoid, bone and abortive cartilaginous elements were present (Fig. More


[1 Apr 2015 | No Comment | 1,871 views]
April 2015: A 32 year old man with a soft tissue mass adjacent to the right humerus

History: A 32-year-old man presented with a mass in the right arm. It involved the humerus and upon excision was 8.2 x 6.5 x 3.5 cm and weighed 52 grams. It consisted mostly of fatty tissue but had a 3.0 x 2.5 cm, vaguely circumscribed nodule centrally located.

H&E staining of the central lesion revealed marked hyperplasia of lymphoid follicles with expanded germinal centers and well-formed mantle zones (Fig. 1). Some of the follicles had intervening fibrosis (… More