Back-to-back: The co-occurrence of DISH and ankylosing spondylitis from early modern Poland.

Objective: This case study evaluates an individual with skeletal changes consistent with DISH and ankylosing spondylitis. We present here an evaluation of the individual's pathological skeletal changes and a review of the potential diagnoses. Finally, we offer a differential diagnosis of co-morbidity infrequently found in the paleopathological record.

Materials: The skeletal remains of a male, aged 50 + years from the early modern Polish (17th-18th century CE) site of Drawsko 1.

Methods: Skeletal remains were examined for the presence of spondyloarthropathies.

Results: The individual presented with anterolateral fusion of the vertebral bodies of T6-T10 with a "dripping candle wax" appearance, fusion of the right costovertebral joint at rib 8, fusion of the left apophyseal joints of T8-T10, and the calcification of the supraspinous ligament at T3-T4. The left sacroiliac joint shows intra-articular and para-articular fusion; the right has bony changes consistent with ongoing fusion. Entheseal reactions were noted on the left clavicle, scapulae, first metacarpals, ulnae, and humerii. Diffuse idiopathic skeletal hyperostosis (DISH), ankylosing spondylitis (AS), reactive arthritis (RA), psoriatic arthritis (PA), and enteropathic arthritis (EA) are considered as differential diagnoses.

Conclusions: Based on the skeletal pattern of involvement, the individual suffered from both DISH and AS, which has previously been reported once in the paleopathological literature since 1950. The clinical literature indicates that co-occurrence of these two conditions is possible, with approximately 40 individuals affected.

Significance: This case study is significant for demonstrating the co-occurrence of DISH and AS in the paleopathological record. Additionally, this case contributes to the understanding of heterogenous frailty and syndemics.

Limitations: No radiographs were taken to confirm the differential diagnosis. No aDNA analysis was conducted.

Suggestions For Further Research: The remains have been reburied; no further analysis is possible.