Muscular Pseudohypertrophy (Steatosis) in a Bovine Fetus

Abstract

Abstract. Muscular pseudohypertrophy was diagnosed in the cervical musculature of a full-term crossbred Simmental fetus delivered by fetotomy. Only head and cervical regions were submitted for pathologic examination; the rest of the fetal body was reportedly normal. The neck musculature of the fetus was markedly deformed by 23 cm and 18 cm in diameter, firm, spherical masses that consisted of enlarged and pale left splenius and right serratus ventralis cervicis muscle, respectively, covered by intact skin. Additionally, lipomatous masses were present within the cervical vertebral canal, compressing the spinal cord. Microscopically, the prominent muscular enlargement was due to massive adipose and fibrous connective tissue replacement of atrophic muscle. Focal myelodysplasia and astrocytosis affecting the grey matter was detected in the mid-cervical region of the spinal cord, accompanied by degeneration in the ascending and descending tracts of the remaining cord segments. Abnormal spinal cord development as a result of severe spinal cord compression by the lipomatous masses within the spinal canal leading to replacement of muscle by fat and fibrous tissue was considered to be the cause of the muscular malformation in this fetus.

Fetal dystocia due to muscular steatosis coupled with ascites and arthrogryposis in Mehsana buffalo

“…In the present case, excessive pseudo-hypertrophy of left splenius, left and right serratuscervicis, brachiocephalicus, and pectoral muscles were observed, while supraspinatus, trapazius, omotransversarius, deltoideus and part of triceps were remarkably either enlarged or atrophied. Gross and histological findings were similar to Langohr et al (2007), and they opined that muscle severity and selective involvement are always associated with a lack of innervation or denervation of affected muscles due to the cervical spinal cord deformation. If the denervation is permanent, it leads to atrophy of the respective muscle.…”

“…The muscular pseudo-hypertrophy involves various cervical and shoulder muscles, either unilaterally or bilaterally. Langohr et al (2007) and Ghuman et al (2012) reported the pseudo-hypertrophy of the left splenius and right serratusventraliscervicis, while Singh et al (2017) reported the hypertrophy of brachiocephalicus, trapazius, sternocephalicus, and serratuscervicis muscles. In the present case, excessive pseudo-hypertrophy of left splenius, left and right serratuscervicis, brachiocephalicus, and pectoral muscles were observed, while supraspinatus, trapazius, omotransversarius, deltoideus and part of triceps were remarkably either enlarged or atrophied.…”

“…Muscular steatosis is the enlargement of atrophied muscle that occurs due to the replacement of muscle fibers with adipose and fibrous tissue in the developing fetus (Valentine and McGavin, 2007). This condition is caused by the presence of the recessive lethal gene, embryological defects of the central nervous system, environmental (including viruses and toxins), localized lack of innervation or denervation secondary to abnormal spinal cord development and muscular damage (Leipold et al, 1983;Langohr et al, 2007). However, the specific etiology is still unknown.…”