Case Description

A 59-year-old woman, monitored for dermatomyositis since 2011, presented with extensive cutaneous calcinosis and infiltrating right breast carcinoma. A 18F-FDG positron emission tomography–computed tomography (PET/CT) scan was conducted for staging, following inconclusive thoraco-abdomino-pelvic CT and bone scintigraphy due to widespread skin calcifications, obstructing the visualization of metastatic locations.

In our examination, we identified a hypermetabolic pathological mass in the upper-inner quadrant of the right breast (standardized uptake value (SUVmax) = 8.3), linked to the primary tumor (Figure 1A). There was also a suspicious hypermetabolic involvement of lymph nodes in the right axillary (SUVmax = 4.2) (Figure 1B) and internal mammary chain. Furthermore, the PET/CT scan indicated the absence of any other pathological hypermetabolic focus in the rest of the body, from the head to mid-thigh. Notably, this was observed despite the presence of discreetly hypermetabolic multiple disseminated subcutaneous calcifications affecting the trunk and the roots of all four limbs, associated with the known extensive cutaneous calcinosis (SUVmax = 2.0) (Figure 2A and 2B).

Calcinosis, a challenging complication associated with juvenile dermatomyositis, can also affect adults [1]. Its unclear pathophysiology often leads to late-stage diagnosis [2]. It generally manifests diffusely, often localizing around the trunk and limbs [3], as observed in our patient (Figures 2 and 3). While clinical examination and histology are commonly used for diagnosis, imaging plays a crucial role in scenarios ranging from diagnostic uncertainty to monitoring the condition’s evolution. Various imaging modalities, such as CT scans, magnetic resonance imaging (MRI), bone scintigraphy (Figure 4), and ultrasound, are mentioned in the literature, with PET/CT being able to reveal areas of hypermetabolism, reflecting inflammation [4]. In our specific case, 18F-FDG PET/CT enabled us to visualize this unusual aspect and perform a comprehensive assessment of breast neoplasia extension due to the metabolic activity and avidity of neoplastic cells for FDG.

Figure 1. Axial fused images of 18F-FDG PET/CT scan revealing a voluminous hypermetabolic pathological mass in the right breast (Panel A) and suspected hypermetabolic pathological right axillary lymphadenopathy (Panel B).

Figure 2. Coronal fused images (Panel A) from 18F-FDG PET/CT and a localization CT scan (Panel B) showing discreetly hypermetabolic subcutaneous calcifications distributed across the trunk and limbs, confirming extensive calcinosis.

Figure 3. Bilateral cutaneous and axillary calcinosis.

Figure 4. 99mTc-HMDP bone scintigraphy: anterior and posterior planar images reveal extensive extra-osseous hyperfixations in the trunk and limbs, indicative of dystrophic calcifications, which have not substantially contributed to the extension assessment of our patient.

References

1. Belaziz F, Nassar K, Rachidi W, Janani S, Mkinsi O. La calcinose sous-cutanée dystrophique associée à la dermatomyosite de l’adulte: effet des immunoglobulines intraveineuses. La Revue de Médecine Interne. 2016;37(Supplement 2):A255. https://doi.org/10.1016/j.revmed.2016.10.357
2. Bayou F, Belajouza C, Boussofara L, Ghariani N, Denguezli M, Bouajina E, et al. Calcinose universelle agressive compliquant une dermatomyosite. Ann Dermatol Vénéréol. 2011;138(11):758–60. https://doi.org/10.1016/j.annder.2011.06.003
3. Korsaga-Somé N, Traoré F, Diallo B, Andonaba JB, Ouédraogo MS, Tapsoba P, et al. Calcinose cutanée massive et diffuse compliquant une dermatomyosite de l’adulte. Ann Dermatol Vénéréol. 2015;142(3):229–30. https://doi.org/10.1016/j.annder.2015.01.004.
4. Helali W, Boukhris I, Hariz A, Kechaou I, Hamdi MS, Cherif E, et al. Images de calcinoses sous-cutanées diffuses et rebelles au cours d’une dermatomyosite. La Revue de Médecine Interne. 2019;40:A107–8. https://doi.org/10.1016/j.revmed.2019.10.133